re-evaluation of tortella - Missouri Botanical Garden
re-evaluation of tortella - Missouri Botanical Garden
re-evaluation of tortella - Missouri Botanical Garden
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Bulletin <strong>of</strong> the Buffalo Society <strong>of</strong> Natural Sciences 36: 117 - 191. 1998.<br />
© 1998 The Buffalo Museum <strong>of</strong> Science<br />
RE-EVALUATION OF TORTELLA (MUSCI, POTTIACEAE) IN CONTERMINOUS U.S.A.<br />
AND CANADA WITH A TREATMENT OF THE EUROPEAN SPECIES TORTELLA NITIDA<br />
Patricia M. Eckel<br />
Division <strong>of</strong> Botany, Buffalo Museum <strong>of</strong> Science, 1020 Humboldt Parkway, Buffalo, New York 14211<br />
Abstract. The moss genus Tortella (Pottiaceae) is <strong>re</strong>-examined for continental North America north <strong>of</strong> Mexico.<br />
Tortella alpicola is distinguished from T. fragilis as an uncommon but widesp<strong>re</strong>ad taxon. Tortella japonica is<br />
conside<strong>re</strong>d to be a minor variant <strong>of</strong> T. humilis. Tortella rigens is new to the United States on the basis <strong>of</strong> comparison<br />
<strong>of</strong> American material with that <strong>of</strong> Europe, p<strong>re</strong>vious <strong>re</strong>ports being erroneous. Tortella nitida is <strong>re</strong>described from<br />
authentic material and is excluded from the North American flora. The hitherto European Tortella tortuosa var.<br />
fragilifolia is <strong>re</strong>ported from American plant populations. Tortella inclinata var. densa is <strong>re</strong>ported as new to North<br />
America as a comb. nov. The bipolar distribution <strong>of</strong> Tortella fragilis is confirmed. Tortella inclinata var. inclinata is<br />
excluded from the flora <strong>of</strong> Arctic North America—specimens on which the species we<strong>re</strong> cited we<strong>re</strong> found to be T.<br />
inclinata var. densa instead.<br />
This study <strong>of</strong> the genus Tortella in continental North<br />
American north <strong>of</strong> Mexico was especially undertaken to<br />
add<strong>re</strong>ss certain problematic taxa. An attempt was made<br />
to <strong>re</strong>solve past ambiguities by focusing on anatomical<br />
and morphological characters, for example to<br />
distinguish between the <strong>re</strong>latively common T. fragilis<br />
(Drumm.) Limpr. and a hitherto <strong>re</strong>latively unknown<br />
element in Tortella, T. alpicola Dix.<br />
Zander (1994d) added Tortella japonica<br />
(Besch.) Broth. to the Mexican flora, drawing attention<br />
to the <strong>re</strong>lationship between the Japanese and Mexican<br />
floras. This c<strong>re</strong>ated problems in separation <strong>of</strong> similar<br />
specimens with a broad distribution in Canada and the<br />
United States from the widesp<strong>re</strong>ad northern hemisphe<strong>re</strong><br />
species T. humilis (Hedw.) Jenn. The decision that these<br />
two taxa a<strong>re</strong> conspecific <strong>re</strong>veals g<strong>re</strong>ater variability in<br />
Tortella humilis than p<strong>re</strong>viously <strong>re</strong>cognized, and<br />
confirms the widesp<strong>re</strong>ad distribution <strong>of</strong> that species.<br />
One <strong>of</strong> the consequences <strong>of</strong> determinations<br />
made during this study is to <strong>re</strong>late the Tortella flora <strong>of</strong><br />
North America mo<strong>re</strong> closely with that <strong>of</strong> a<strong>re</strong>as <strong>of</strong><br />
Europe; it also emphasizes the Old-World endemism <strong>of</strong><br />
the species T. nitida by excluding it from the New.<br />
Two taxa, Tortella tortuosa var. fragilifolia<br />
and T. alpicola, conflated in p<strong>re</strong>vious concepts <strong>of</strong> T.<br />
nitida for North America, have been <strong>re</strong>defined such that<br />
claims <strong>of</strong> variability in T. tortuosa in the European<br />
literatu<strong>re</strong> can be <strong>re</strong>lated to similar variability in the New<br />
World.<br />
Recognition <strong>of</strong> only two varieties <strong>of</strong> Tortella<br />
tortuosa for the enti<strong>re</strong> North American continent north<br />
<strong>of</strong> Mexico, a species cur<strong>re</strong>ntly well known for its<br />
protean natu<strong>re</strong>, may provide a mo<strong>re</strong> conservative basis<br />
for the justification <strong>of</strong> <strong>re</strong>cognizing some <strong>of</strong> the<br />
described European varieties <strong>of</strong> T. tortuosa as species in<br />
their own right. Such <strong>re</strong>cognition might have<br />
biogeographic significance in postulating a higher<br />
species diversity for the genus in, for example, the<br />
<strong>re</strong>gion <strong>of</strong> the Alps or southern (Mediterranean) Europe,<br />
Northern Africa and islands in the Atlantic.<br />
Tortella alpicola, as T. fragilis var. tortelloides<br />
S. W. G<strong>re</strong>ene, once claimed to be conspecific to or<br />
intermediate between T. tortuosa and T. fragilis, has<br />
maintained its distinctiveness throughout its range as a<br />
cordilleran species, but with a world-wide distribution<br />
similar to that <strong>of</strong> Molendoa sendtneriana (Bruch &<br />
Schimp.) Limpr.<br />
The discovery <strong>of</strong> Tortella rigens in the<br />
limestone alvars <strong>of</strong> the G<strong>re</strong>at Lakes <strong>re</strong>gion <strong>re</strong>lates the<br />
biogeography <strong>of</strong> those a<strong>re</strong>as in North America with that<br />
<strong>of</strong> Europe, particularly <strong>of</strong> the circum-Baltic <strong>re</strong>gion, and<br />
promises to contribute to post-glacial floristic<br />
<strong>re</strong>constructions <strong>of</strong> these inte<strong>re</strong>sting a<strong>re</strong>as. The discovery<br />
<strong>of</strong> another taxon largely distributed in the North<br />
American bo<strong>re</strong>al zone, morphologically close to T.<br />
inclinata and T. rigens, identified with the European T.<br />
densa (Lor. & Mol.) Crundw. & Nyh., may be included<br />
in analyses <strong>of</strong> northern vegetational histories. It is he<strong>re</strong><br />
t<strong>re</strong>ated as a variety <strong>of</strong> Tortella inclinata.<br />
The p<strong>re</strong>sent study <strong>re</strong>cognizes seven species <strong>of</strong><br />
the genus p<strong>re</strong>sent in North America, and th<strong>re</strong>e varieties.<br />
TORTELLA<br />
Tortella (Lindb.) Limpr., Laubm. Deutschl. 1: 599.<br />
1888, nom. cons. [Latin tortus, twisted, and -<br />
ella, a diminutive, in <strong>re</strong>fe<strong>re</strong>nce to the twisted<br />
peristome teeth]<br />
Mollia subg. Tortella Lindb., Musci Scand. 21.<br />
1879.<br />
Barbula sect. Tortella C. Müll., Syn. 1: 599.<br />
1849, nom. illeg. incl. sect. prior.<br />
Barbula subg. Tortella (Lindb.) Kindb., Eur.<br />
N. Amer. Bryin. 2: 245. 1897.<br />
Mollia sect. Tortella (Lindb.) Braithw., Brit.<br />
Moss Fl. 1: 230. 1885.<br />
Plants small to medium-sized, in loose or dense tufts or<br />
mats or expanded in compact sods, fragile, dull g<strong>re</strong>en,<br />
yellowish to dark g<strong>re</strong>en above, black, brown or tan<br />
below with prominent shining costae. Stems e<strong>re</strong>ct, <strong>of</strong>ten<br />
branched, in transverse section with hyalodermis,
somewhat weak sclerodermis, central strand absent or<br />
p<strong>re</strong>sent, rhizoids dense or few at the base, occasionally<br />
tomentose; axillary hairs long, 10–20 cells in length,<br />
hyaline. Stem leaves cirrhate-crispate to incurved when<br />
dry, sp<strong>re</strong>ading to <strong>re</strong>curved when moist, elongate-oblong<br />
to linear-lanceolate or linear-subulate, widest at or near<br />
the base; base hyaline, oblong, e<strong>re</strong>ct; margins plane to<br />
incurved above, generally enti<strong>re</strong> and minutely c<strong>re</strong>nulate<br />
by projecting papillae, but <strong>of</strong>ten slightly or ir<strong>re</strong>gularly<br />
scalloped through indentations at points <strong>of</strong> laminal<br />
weakness, occasionally somewhat to strongly undulate,<br />
ra<strong>re</strong>ly with a border <strong>of</strong> elongate, clear, smooth cells in<br />
one series above midleaf, gradually tapering upward or<br />
mo<strong>re</strong> or less abruptly narrowed; apex acute or obtuse,<br />
cucullate or concave, tipped with an apiculus, mucro or<br />
short subula; costa strong, percur<strong>re</strong>nt to short-excur<strong>re</strong>nt,<br />
adaxial and abaxial epidermal cells <strong>of</strong>ten p<strong>re</strong>sent, two<br />
ste<strong>re</strong>id bands, one layer <strong>of</strong> median guide cells p<strong>re</strong>sent,<br />
hydroid strand occasionally p<strong>re</strong>sent; proximal cells<br />
enlarged, laxly long-<strong>re</strong>ctangular, thin-walled, hyaline,<br />
occasionally brown and rather thick-walled, smooth,<br />
abruptly diffe<strong>re</strong>ntiated from the g<strong>re</strong>en cells distally or<br />
gradual in transition, limit <strong>of</strong> the proximal <strong>re</strong>gion<br />
usually appears as a V-shape, the limit extending up<br />
each leaf margin as a short or elongated border; distal<br />
laminal cells medially and distally rounded-hexagonal,<br />
chlorophyllose, f<strong>re</strong>quently obscu<strong>re</strong>d by numerous,<br />
dense, C-shaped papillae on both surfaces. Asexual<br />
<strong>re</strong>production at the stem apex occasional, by deciduous<br />
or fragile propaguloid leaf tips, or by deterioration <strong>of</strong><br />
fragile leaves along zones <strong>of</strong> laminal weakness. Sexual<br />
condition: dioicous, occasionally autoicous. Perigonia<br />
terminal, short-foliose to gemmate or as stalked buds in<br />
leaf axils <strong>of</strong> perichaetiate plants. Perichaetia terminal,<br />
leaves not or little diffe<strong>re</strong>ntiated, or distinct and longsetaceous.<br />
Seta 1(–2) per perichaetium, yellow or<br />
<strong>re</strong>ddish below with age, to 3 cm long, e<strong>re</strong>ct, smooth;<br />
capsule e<strong>re</strong>ct and symmetric or slightly inclined, yellow<br />
to <strong>re</strong>ddish brown with a darker <strong>re</strong>d or brown color to the<br />
mouth, elliptic to cylindric, mo<strong>re</strong> or less wrinkledplicate<br />
when dry and empty; annulus sometimes p<strong>re</strong>sent,<br />
<strong>of</strong> 1–4 rows <strong>of</strong> vesiculose cells, persistent; operculum<br />
conic or long-rostrate, half as long as the urn or longer,<br />
straight or inclined; peristome orange-<strong>re</strong>d, single, welldeveloped<br />
from a low basal membrane, <strong>of</strong> 32 filiform<br />
rami joined at the base into 16 pairs, twisted<br />
counterclockwise or me<strong>re</strong>ly obliquely inclined,<br />
branched-spiculose, ra<strong>re</strong>ly nearly smooth. Calyptra<br />
cucullate, smooth. Spo<strong>re</strong>s 8–12(–20) µm in diameter,<br />
yellowish brown, moderately coarsely to finely<br />
papillose to nearly smooth.<br />
Species: 53, 7 in the flora, cf. Zander (1993).<br />
Found on soil, rock or organic substrates in dry<br />
to variably moist habitats on all continents, generally<br />
associated with but not confined to calca<strong>re</strong>ous habitats.<br />
North American species a<strong>re</strong> all smooth on the<br />
back <strong>of</strong> the costa except at the ext<strong>re</strong>me ends <strong>of</strong><br />
propaguloid leaf tips. This smoothness gives plants a<br />
distinctive shining costa in sharp contrast to the g<strong>re</strong>en <strong>of</strong><br />
2<br />
the lamina, which is dulled by papillae on the surface<br />
<strong>of</strong> the leaf cells.<br />
The pottiaceous genus Trichostomum Bruch is<br />
similar in leaf shape and margin flexion, but has distal<br />
laminal cells diffe<strong>re</strong>ntiated from the proximal cells in a<br />
line straight across the leaf base or in a low "U", i.e.,<br />
straight across but with some smooth, hyaline,<br />
elongated proximal cells extending up the leaf margins<br />
above the leaf shoulder. The proximal-cell line <strong>of</strong><br />
diffe<strong>re</strong>ntiation usually forms a distinct V-shape in<br />
Tortella. The peristomes <strong>of</strong> Trichostomum a<strong>re</strong> e<strong>re</strong>ct,<br />
<strong>of</strong>ten short and f<strong>re</strong>quently smooth, whe<strong>re</strong>as those <strong>of</strong><br />
Tortella a<strong>re</strong> long and twisted generally 2–3 times (only<br />
slightly so in T. flavovi<strong>re</strong>ns) and densely spiculose in<br />
non cleistocarpous species (see Zander 1993). In much<br />
<strong>of</strong> the literatu<strong>re</strong> the peristomes <strong>of</strong> Tortella a<strong>re</strong> described<br />
as papillose, when they a<strong>re</strong> actually spiculose: all<br />
peristomes <strong>of</strong> the species t<strong>re</strong>ated in this paper have<br />
spiculose peristome teeth. The term "papillae" may then<br />
be mo<strong>re</strong> usefully employed in the t<strong>re</strong>atment <strong>of</strong> genera<br />
with peristome ornamentation that is <strong>of</strong> tiny, rounded,<br />
nipple-like or pimple-like elevations such as some<br />
species, for example, in the genera Trichostomum and<br />
Pseudosymblepharis Broth.<br />
Plerurochaete Lindb. does not have the Vshaped<br />
a<strong>re</strong>a <strong>of</strong> diffe<strong>re</strong>ntiated hyaline proximal<br />
echlorophyllose cells as in Tortella, but has a median<br />
a<strong>re</strong>a <strong>of</strong> gradually diffe<strong>re</strong>ntiated proximal cells and a<br />
strong border <strong>of</strong> several rows <strong>of</strong> cells contrasting with<br />
both laminal and proximal cells in being abruptly<br />
longer, thinner-walled, smooth and without chlorophyll.<br />
Plerurochaete also has perichaetia, in addition to<br />
perigonia, borne laterally on short branches on the main<br />
axis <strong>of</strong> the plant. The genus St<strong>re</strong>ptocalypta C. Müll., <strong>of</strong><br />
which two species a<strong>re</strong> endemic to Mexico, also<br />
<strong>re</strong>sembles Tortella, having abruptly diffe<strong>re</strong>ntiated<br />
proximal cells extending up the leaf margins in a Vshape.<br />
It is separated from Tortella by the e<strong>re</strong>ct<br />
peristome teeth and distinctive costal anatomy, the<strong>re</strong><br />
being no or ra<strong>re</strong>ly a small group <strong>of</strong> adaxial ste<strong>re</strong>id cells,<br />
but instead several layers <strong>of</strong> variously thick-walled<br />
guide cells adaxial to a well developed abaxial ste<strong>re</strong>id<br />
band.<br />
Because the genus Trichostomum has been<br />
conside<strong>re</strong>d closely <strong>re</strong>lated to Weissia Hedw., Tortella,<br />
<strong>re</strong>latively <strong>re</strong>cently seg<strong>re</strong>gated from Trichostomum, has<br />
been thought to sha<strong>re</strong> in this proximity. Species in<br />
Weissia a<strong>re</strong> similar to Tortella by the incurving leaf<br />
margins (generally strongly and sharply incurved<br />
throughout the leaf length) with a tendency toward<br />
cucullation in the leaf apex. The proximal cells <strong>of</strong> some<br />
Weissia species may extend slightly up the margins, as<br />
in species <strong>of</strong> Trichostomum, and most especially,<br />
Weissia jamaicensis (Mitt.) Grout <strong>re</strong>sembles a Tortella<br />
by a proximal <strong>re</strong>gion with a V-shape. After subjecting<br />
the genera in the Pottiaceae to cladistic analyses, Zander<br />
(1993) has produced a phylogenetic <strong>evaluation</strong> <strong>of</strong> the<br />
family with novel arrangements <strong>of</strong> genera, one <strong>re</strong>sult<br />
placing Weissia in a group (Hyophileae) in the<br />
Pottioideae with genera such as Hyophila,
Weissiodicranum and Weisiopsis, far from its traditional<br />
grouping in the Trichostomoideae. An important aspect<br />
<strong>of</strong> the new arrangement is the grouping <strong>of</strong> genera,<br />
including Weissia, with others that have bulging cells on<br />
the adaxial surface <strong>of</strong> the leaf <strong>re</strong>lative to the flat abaxial<br />
surface.<br />
As for Weissia jamaicensis, we<strong>re</strong> this species<br />
<strong>re</strong>moved from that genus and placed instead in a group<br />
<strong>of</strong> taxa, such as the Chionolomoideae (Zander 1993),<br />
comprised <strong>of</strong> Chionoloma, Pseudosymblepharis and<br />
Pachyneuropsis, genera with many morphological and<br />
possibly distributional characteristics sha<strong>re</strong>d by this<br />
species, the genus Weissia may display a mo<strong>re</strong> natural<br />
distance from the Trichostomoideae. Unlike many<br />
species in the genus Weissia, W. jamaicensis is<br />
dioicous, it has a massive adaxial ste<strong>re</strong>id band c<strong>re</strong>ating a<br />
strongly convex adaxial pr<strong>of</strong>ile in section, an elongate<br />
leaf, such as others in the Chionolomoideae, and other<br />
characteristics that a<strong>re</strong> suggestive <strong>of</strong> a diffe<strong>re</strong>nt<br />
placement <strong>of</strong> this species.<br />
One rather distinctive characteristic <strong>of</strong> the<br />
genus Tortella is the flattened, foliose, stalked<br />
perigonial buds <strong>of</strong> some species. Only one <strong>of</strong> the taxa<br />
he<strong>re</strong> studied possesses them: Tortella humilis. The<strong>re</strong> is,<br />
however, a group <strong>of</strong> species <strong>of</strong> the genus that exhibit<br />
this character, listed by Brotherus (1924–25). The<strong>re</strong> a<strong>re</strong><br />
species in the genus Trichostomum with these, such as<br />
Trichostomum fragilifolium Dix., and Trichostomum<br />
spirale Grout, and at least St<strong>re</strong>ptocalypta tortelloides<br />
(Card.) Zand., <strong>of</strong> the four species <strong>re</strong>cognized for that<br />
genus (Zander 1993), also has them. Again, in the genus<br />
Plerurochaete, whe<strong>re</strong> all the species a<strong>re</strong> dioicous, the<br />
perigonia (and perichaetia) a<strong>re</strong> <strong>re</strong>gularly stalked. These<br />
genera in the Trichostomoideae may be <strong>re</strong>lated by this<br />
tangential similarity, perhaps through a <strong>re</strong>duction series<br />
in the peristome.<br />
In the following t<strong>re</strong>atment, g<strong>re</strong>at emphasis has<br />
been put on the cross section <strong>of</strong> the distal <strong>re</strong>gion <strong>of</strong> the<br />
leaf in delimiting taxa and for discussing <strong>re</strong>lationships.<br />
Although some bryologists do not ca<strong>re</strong> to employ this<br />
technique, nor a<strong>re</strong> stem and leaf sections <strong>of</strong>ten<br />
conside<strong>re</strong>d to be significant in determining taxonomic<br />
limits at the species level, yet details about these<br />
characters we<strong>re</strong> employed to assess the concepts <strong>of</strong><br />
earlier students. It was found during the course <strong>of</strong> this<br />
study that these characters do in fact aid in identification<br />
<strong>of</strong> specimens.<br />
Some <strong>re</strong>cent floristic t<strong>re</strong>atments <strong>of</strong> the genus<br />
have tended to group species with mo<strong>re</strong> or less ligulate<br />
leaves and obtuse apices as seg<strong>re</strong>gated from those with<br />
lanceolate leaves. In the p<strong>re</strong>sent study, Tortella humilis<br />
is p<strong>re</strong>sumed to be associated with T. flavovi<strong>re</strong>ns and T.<br />
nitida on the basis <strong>of</strong> the strong stem central strand, the<br />
variously gradually diffe<strong>re</strong>ntiated proximal cells, with a<br />
border <strong>of</strong> elongated, smooth, thin-walled and lax cells<br />
mo<strong>re</strong> or less confined to the border in some or all<br />
leaves. This characteristic set, together with the stalked<br />
perigonial bud <strong>of</strong> T. humilis seems to associate the<br />
group with the genus Plerurochaete as noted above, but<br />
also with Trichostomum, some species <strong>of</strong> which have a<br />
3<br />
hint <strong>of</strong> a marginal border and some have stalked<br />
perigonial buds. The somewhat <strong>re</strong>duced peristome with<br />
e<strong>re</strong>ct teeth also suggests that last genus as do the<br />
undiffe<strong>re</strong>ntiated perichaetial leaves. St<strong>re</strong>ptocalypta has a<br />
<strong>re</strong>duced peristome and stalked perigonial buds in one <strong>of</strong><br />
the th<strong>re</strong>e species, and undiffe<strong>re</strong>ntiated perichaetial<br />
leaves.<br />
Tortella alpicola, hitherto discussed (see<br />
below) as <strong>re</strong>lated to or as a variety <strong>of</strong> T. tortuosa or T.<br />
fragilis, actually is distinguished by the consistent<br />
p<strong>re</strong>sence <strong>of</strong> a stem central strand. The absence or poor<br />
development <strong>of</strong> an adaxial ste<strong>re</strong>id band in the leaf seems<br />
to suggest St<strong>re</strong>ptocalpyta; this characteristic, however,<br />
also applies to the var. fragilifolia <strong>of</strong> Tortella tortuosa.<br />
The perichaetial leaves a<strong>re</strong> the same as those <strong>of</strong> T.<br />
tortuosa. I shall speculate that Tortella alpicola will<br />
prove to have a nearly cosmopolitan distribution and in<br />
fact be <strong>re</strong>latively ancestral to a T. tortuosa complex.<br />
One need only <strong>re</strong>fer to the large number <strong>of</strong> infraspecific<br />
taxa accorded to T. tortuosa in Europe to posit such a<br />
complex. The literatu<strong>re</strong> <strong>of</strong> T. alpicola seems to imply<br />
that it is a <strong>re</strong>latively <strong>re</strong>cent species when in fact it may<br />
be one <strong>of</strong> the mo<strong>re</strong> ancient in the Tortella group.<br />
The fact that Tortella tortuosa in the enti<strong>re</strong><br />
North American continent, including Mexico, can be<br />
accorded only two varieties, one in the ext<strong>re</strong>me north<br />
(Arctic) or at ext<strong>re</strong>mely high altitudes and the other only<br />
a vaguely defined entity associated with moderately<br />
high elevations in the Temperate-Bo<strong>re</strong>al zone, might be<br />
useful in distinguishing species limits in what appears to<br />
be a welter <strong>of</strong> intergrading forms in Europe. Tortella<br />
fragilis may be conside<strong>re</strong>d a derived form <strong>of</strong> Tortella<br />
tortuosa through the variety fragilifolia along the lines<br />
conceived by Dixon (1924).<br />
Another group <strong>re</strong>lated to Tortella tortuosa<br />
through diffe<strong>re</strong>ntiated perichaetial leaves, absence <strong>of</strong> a<br />
stem central strand, sharply distinguished V-shape to the<br />
proximal cell <strong>re</strong>gion, and long, spirally twisted<br />
peristome, may be Tortella inclinata, T. densa (he<strong>re</strong><br />
t<strong>re</strong>ated as varieties <strong>of</strong> T. inclinata) and T. rigens. It has<br />
been speculated that Tortella rigens may sha<strong>re</strong> some <strong>of</strong><br />
the genes <strong>of</strong> T. fragilis (see discussion below).<br />
Tortella inclinata var. densa has not been<br />
<strong>re</strong>ported for the North American flora, while T. rigens<br />
has but based on erroneous and p<strong>re</strong>matu<strong>re</strong><br />
determinations. The concept <strong>of</strong> these two taxa and <strong>of</strong><br />
Tortella inclinata employed <strong>re</strong>cently by Crundwell and<br />
Nyholm in various publications (particularly Crundwell<br />
& Nyholm 1962; Nyholm 1989) does not fit exactly<br />
with North American material in some <strong>re</strong>spects, but<br />
seems to be the most useful to explain the p<strong>re</strong>sence and<br />
distribution <strong>of</strong> these th<strong>re</strong>e taxa and their substrates in the<br />
<strong>re</strong>gion.<br />
In consideration <strong>of</strong> the glacial-geological<br />
implications <strong>of</strong> the substrates <strong>of</strong> these th<strong>re</strong>e taxa in the<br />
North American situation, one might speculate that<br />
plants <strong>of</strong> Tortella inclinata var. densa that occur in<br />
upland (rock c<strong>re</strong>vices) situations might be associated<br />
with glacial <strong>re</strong>fugia (or at least mo<strong>re</strong> stable habitats),<br />
Tortella inclinata var. inclinata with the constantly
shifting but widesp<strong>re</strong>ad distribution <strong>of</strong> alluvial deposits<br />
north <strong>of</strong> or at the border <strong>of</strong> glaciation, and T. rigens with<br />
the alvar substrates c<strong>re</strong>ated by scouring water<br />
terminated suddenly (perhaps by st<strong>re</strong>am captu<strong>re</strong> in the<br />
scenario <strong>of</strong> <strong>re</strong>t<strong>re</strong>ating continental glaciers) so that their<br />
4<br />
beds become suba<strong>re</strong>al with little or no sedimentary<br />
deposition.<br />
Herbarium codes a<strong>re</strong> according to Holmg<strong>re</strong>n et<br />
al. (1990).<br />
KEY TO THE SPECIES OF TORTELLA IN NORTH AMERICA NORTH OF MEXICO<br />
1. Leaves oblong-lanceolate or elliptical, apex broadly acute to obtuse, sometimes cucullate . . . . 2<br />
2. Autoicous, nearly always fruiting; distal margins plane to e<strong>re</strong>ct, apex broadly acute; distal leaf cells<br />
about 6–7 µm; central strand p<strong>re</strong>sent; cells on adaxial surface <strong>of</strong> the costa quadrate and papillose<br />
throughout most <strong>of</strong> its length; stems short; plants typically rosulate, densely foliose, widesp<strong>re</strong>ad in the East,<br />
ra<strong>re</strong> in the West . . . . 1. Tortella humilis<br />
2. Dioicous, seldom fruiting; distal margins incurved to strongly or variably cucullate at the apex, apex<br />
obtuse; distal leaf cells 7–11(–14) µm in diameter; central strand p<strong>re</strong>sent or absent; cells on adaxial surface<br />
<strong>of</strong> the costa quadrate and papillose throughout most <strong>of</strong> their length or mostly or enti<strong>re</strong>ly elongate and<br />
smooth; stems elongate; plants loosely foliose . . . . 3<br />
3. Stem central strand p<strong>re</strong>sent; costa with adaxial epidermis: a<strong>re</strong>as on the adaxial surface <strong>of</strong> the<br />
costa with quadrate papillose cells; leaf apex variably somewhat cucullate, acute or obtuse with<br />
apical margins incurved; leaves flat in the leaf middle; fertilized perichaetial leaves not much<br />
diffe<strong>re</strong>ntiated, mosses <strong>of</strong> the coast <strong>of</strong> southeastern United States or Europe . . . . 4<br />
4. Leaves not fragile, apices <strong>of</strong> all leaves p<strong>re</strong>sent; nearly always some leaf apices<br />
cucullate or subcucullate; distal laminal cells 10–12 µm wide; proximal cells abruptly<br />
diffe<strong>re</strong>ntiated at least in larger leaves, thin-walled proximal cell <strong>re</strong>gion extending up the<br />
margin into the limb; radicles sparse, confined to the stem base; guide cells never with<br />
bistratose pairs; mosses exclusively <strong>of</strong> coastal North Carolina south to Florida and west<br />
to Texas . . . . 2. Tortella flavovi<strong>re</strong>ns<br />
4. Leaves fragile, apices <strong>of</strong> nearly all leaves absent; leaf apices inf<strong>re</strong>quently subcucullate,<br />
sometimes distal margin incurved; distal laminal cells 6–10 µm wide; cells gradually<br />
diffe<strong>re</strong>ntiated and thick-walled in the proximal cell <strong>re</strong>gion in all leaves, except for a<br />
narrow marginal border <strong>of</strong> thin-walled cells extending up the margin a short way into the<br />
limb; tomentose in proximal stem <strong>re</strong>gion; guide cells occasionally with bistratose pairs;<br />
plants <strong>of</strong> Europe only . . . . 8. Tortella nitida<br />
3. Stem central strand absent; costa without adaxial epidermis: adaxial surface <strong>of</strong> the costa with<br />
smooth, elongate cells throughout the leaf length; leaf apex distinctly cucullate, occasionally<br />
acute, leaves tubulose; fertilized perichaetial leaves conspicuously diffe<strong>re</strong>ntiated, with subulate<br />
tips; mosses <strong>of</strong> the G<strong>re</strong>at Lakes <strong>re</strong>gion and north . . . . 5<br />
5. Leaf cells 11–12 µm or less, stems orange to g<strong>re</strong>enish yellow-brown, leaves deep<br />
yellow or orange in KOH; leaves ir<strong>re</strong>gularly or uniformly twisted on the stem; leaf apices<br />
usually cucullate to narrowly acute, not deciduous; leaves in section usually keeled at the<br />
costa, margins incurved; in rock c<strong>re</strong>vices or unconsolidated alluvial sediments near water<br />
. . . . 6. Tortella inclinata<br />
5. Leaf cells averaging 14 µm; stems dark-g<strong>re</strong>en to brown, leaves g<strong>re</strong>en in KOH; leaves<br />
e<strong>re</strong>ct, twisted only at the stem tips; leaf apices variable, usually acute to acuminate, never<br />
uniformly cucullate, f<strong>re</strong>quently with a narrowed apical deciduous point; leaves in section<br />
broadly tubulose; mosses <strong>of</strong> limestone pavements with thin soil cover (alvar) in the G<strong>re</strong>at<br />
Lakes <strong>re</strong>gion . . . . 7. Tortella rigens<br />
1. Leaves narrowly short to long- to linear-lanceolate, not cucullate or obtuse, apex narrowly acute, tapering to an<br />
acuminate point, sometimes apex very long, with a long, setaceous point . . . . 6<br />
6. Leaves without apical propaguloid modifications although some apices may be somewhat fragile . . . . 7<br />
7. Stems with central strand, leaf cells ca. 14 µm . . . . 3. Tortella alpicola<br />
7. Stems without central strand, or this ra<strong>re</strong>, leaf cells to 14 µm but <strong>of</strong>ten less . . . . 8<br />
8. Leaves tubulose, margins broadly incurved; most distal laminal cells 14 µm; quadrate,<br />
papillose adaxial cells on the surface <strong>of</strong> the costa absent throughout the leaf length to a<br />
width <strong>of</strong> two or th<strong>re</strong>e cells in section; leaf apices deciduous; known from limestone<br />
pavements in the G<strong>re</strong>at Lakes <strong>re</strong>gion . . . . 7. Tortella rigens<br />
8. Leaves plane to canaliculate, margins plane to e<strong>re</strong>ct; distal laminal cells seldom<br />
attaining 12 µm, usually less; quadrate, papillose adaxial cells on the surface <strong>of</strong> the costa<br />
p<strong>re</strong>sent in the median leaf <strong>re</strong>gion or higher; <strong>of</strong> general temperate to Arctic distribution . .<br />
. . 4. Tortella tortuosa
5<br />
6. Leaves with distinctive apical propaguloid modifications, leaf apices <strong>re</strong>gularly fallen . . . . 9<br />
9. Stems 1–5 cm, coarsely tomentose; central strand absent; distal leaves to 7 mm, densely<br />
crowded, rigid, with patches <strong>of</strong> elongated, non-papillose cells on distal leaf margins <strong>of</strong> young<br />
leaves at the stem apex; leaf cells 10–12 µm; lamina below subula bistratose; apical propagula<br />
falling in a single rigid unit; subulate limb bistratose to multistratose . . . . 5. Tortella fragilis<br />
9. Stems 0.5 to 1.5 cm, scarcely or not tomentose, central strand p<strong>re</strong>sent; distal leaves 1.5–2.0 mm,<br />
sparse, s<strong>of</strong>t, leaf tips without diffe<strong>re</strong>ntiated marginal cells; leaf cells 14 µm; lamina unistratose<br />
throughout the leaf; propaguloid leaves and apical propagula articulated by periodic constrictions<br />
falling in several pieces; leaves bistratose only in patches or along costa distally . . . . 3. Tortella<br />
alpicola<br />
1. TORTELLA HUMILIS Plate 1<br />
Tortella humilis (Hedw.) Jenn., Man. Mosses W. Pa. 96.<br />
1913.<br />
Barbula humilis Hedw., Sp. Musc. 116. 1801.<br />
Barbula caespitosa Schwaegr., Suppl. Sp.<br />
Musc. 1: 120. 1811.<br />
Tortella caespitosa (Schwaegr.) Limpr.,<br />
Laubm. Deutschl. 1: 600. 1888.<br />
Trichostomum japonicum Besch., J. de Bot. 12:<br />
295. 1898, syn. nov. Type: Japan,<br />
Arima pr‚s de Kob‚, L. Roux, May 10,<br />
1894 (PC—holotype).<br />
Tortella japonica (Besch.) Broth. in Engler &<br />
Prantl, Nat. Pfl. 1(3): 397. 1902, syn.<br />
nov.<br />
Plants in loose to dense tufts, usually dull and dark<br />
g<strong>re</strong>en to sordid yellow-g<strong>re</strong>en above, brown to black<br />
below, typically compact and rosulate to mo<strong>re</strong> elongate<br />
and showing annual whorls. Stems: nearly stemless or<br />
stems to 0.5(–0.7) cm, central strand distinct, densely<br />
radiculose with <strong>re</strong>d-brown radicles or inf<strong>re</strong>quently<br />
populations with elongate stems without tomentum.<br />
Stem leaves densely foliose in rosulate habits, mo<strong>re</strong><br />
loosely in elongate habits, nearly isomorphic, abruptly<br />
larger above the whorl-bases consisting <strong>of</strong> small leaves,<br />
loosely and variously incurled and contorted,<br />
occasionally somewhat crisped when dry, widesp<strong>re</strong>ading<br />
to patent when moist, typically oblong or<br />
oblong-spathulate, in elongate forms mo<strong>re</strong> ligulatelanceolate<br />
to linear-lanceolate, most leaves flat at<br />
midleaf, somewhat concave and weakly keeled near the<br />
apex, not cucullate; 1.5–3.5(–4) mm; base sub-clasping<br />
and <strong>of</strong>ten appearing narrower than the limb to somewhat<br />
broader and elliptic; margins flat to weakly and broadly<br />
undulate, e<strong>re</strong>ct or broadly incurved near the apex; apex<br />
typically obtuse to broadly or occasionally narrowly<br />
acute, usually stoutly mucronate, apices usually<br />
somewhat twisted due to one side <strong>of</strong> the lamina<br />
somewhat shorter than the other; costa short-excur<strong>re</strong>nt,<br />
adaxial surface papillose, adaxial epidermal cells<br />
typically quadrate to short-<strong>re</strong>ctangular and similar to the<br />
laminal cells throughout, sometimes smooth and<br />
narrowly elongate cells (8:1) toward the apex due to<br />
exposu<strong>re</strong> <strong>of</strong> the ste<strong>re</strong>id band or, in the ext<strong>re</strong>me apex,<br />
exposu<strong>re</strong> <strong>of</strong> the guide cells; in cross section adaxial<br />
epidermis p<strong>re</strong>sent, <strong>of</strong>ten interrupted in the ext<strong>re</strong>me distal<br />
portion <strong>of</strong> the leaf, adaxial and abaxial ste<strong>re</strong>id bands and<br />
one layer <strong>of</strong> guide cells p<strong>re</strong>sent; proximal laminal cells<br />
rather gradually diffe<strong>re</strong>ntiated from distal cells with an<br />
zone <strong>of</strong> cells intermediate in color, cell size, cell wall<br />
thickness and papillosity, yellow-hyaline, elongate,<br />
laxly thin-walled, gradually distally papillose, angle <strong>of</strong><br />
hyaline marginal cell diffe<strong>re</strong>ntiation typically shallow<br />
across the leaf base, then extending up the margins in a<br />
"U" shape, proximal marginal cells <strong>of</strong>ten thicker-walled<br />
than median and juxtacostal cells near the leaf insertion,<br />
which a<strong>re</strong> <strong>of</strong>ten lax and inflated, the latter <strong>of</strong>ten torn on<br />
<strong>re</strong>moval from stem, marginal proximal cells also longer<br />
and larger than median cells, occasionally<br />
approximating a band <strong>of</strong> diffe<strong>re</strong>ntiated cells; proximal<br />
cells interior to the marginal ones gradually<br />
diffe<strong>re</strong>ntiated from the distal laminal cells, those in the<br />
marginal band mo<strong>re</strong> abruptly distinct; distal laminal<br />
cells small, 6–7(–9) mm, 10–13 µm wide in very<br />
elongate forms. Asexual <strong>re</strong>production: modifications<br />
for asexual <strong>re</strong>production none. Sexual condition:<br />
autoicous. Perigonia small, distinctive, stalked,<br />
flattened, usually single, ra<strong>re</strong>ly geminate, f<strong>re</strong>quently<br />
yellow or orange, foliose buds <strong>of</strong> 2–6 leaves in axils <strong>of</strong><br />
the distal leaves alongside and below the perichaetium.<br />
Perichaetial leaves: inner somewhat smaller than the<br />
outer, little diffe<strong>re</strong>ntiated or less f<strong>re</strong>quently abruptly<br />
acuminate-lanceolate, sharply mucronate and sheathing<br />
the seta. Seta at maturity <strong>re</strong>d near the base to pale<br />
yellow-g<strong>re</strong>en above, about (0.5–)0.7–1.7 cm; one per<br />
perichaetium, but <strong>of</strong>ten th<strong>re</strong>e to four per plant from<br />
diffe<strong>re</strong>nt branches. Capsule 1.5–3 mm long; annulus<br />
deciduous in fragments; operculum 1.2–1.5 mm long;<br />
peristome teeth orange-<strong>re</strong>d, to over 1 mm long, spirally<br />
wound 2 or 3 times. Calyptra cucullate. Spo<strong>re</strong>s 10–12<br />
µm, roughened with fine papillae.<br />
Spo<strong>re</strong>s matu<strong>re</strong> in spring.<br />
This wide-ranging species thrives in various<br />
conditions: Thuja swamps and bogs, near st<strong>re</strong>ams, in<br />
hard and s<strong>of</strong>twood fo<strong>re</strong>sts, dry, exposed or moist and<br />
shaded stations, bark at the base <strong>of</strong> t<strong>re</strong>es, acid or basic<br />
substrates, rock c<strong>re</strong>vices and surfaces, sandy or humic<br />
soil, organic debris, mortar and brick, conc<strong>re</strong>te, from<br />
maritime and inland fo<strong>re</strong>sts; from near sea level to<br />
moderate elevations; B.C., N.S., Ont., Que.; Ala., Ariz.,<br />
Ark., Conn., Del., Fla., Ga., Ill., Ind., Iowa, Kans., Ky.,<br />
La., Md., Mich., Minn., Miss., Mo., Nebr., N.C., N.J.,<br />
N.Y., Ohio, Okla., Penn., S.C., Tenn., Tex., Vt., Va.,
Wash., W.Va., Wis.; Mexico, West Indies, South<br />
America, Europe, Asia, Africa, Pacific Islands.<br />
Herbaria examined: BUF, CANM, COLO,<br />
DUKE, FLAS, MICH, MNA, UBC.<br />
Although Tortella tortuosa is the most<br />
common <strong>of</strong> North American species <strong>of</strong> the genus in the<br />
North Temperate and Bo<strong>re</strong>al a<strong>re</strong>as by <strong>re</strong>p<strong>re</strong>sentation in<br />
herbaria, certainly T. humilis warrants this distinction in<br />
eastern middle-temperate and southern <strong>re</strong>gions. With<br />
few exceptions, all specimens examined we<strong>re</strong> fruiting.<br />
The species is so far known to be largely absent west <strong>of</strong><br />
the G<strong>re</strong>at Plains, including the Rocky Mountains and<br />
Basin and Range provinces. The<strong>re</strong> is a disjunctive<br />
population in British Columbia whe<strong>re</strong> it was collected<br />
once, while the southwestern range ends in Arizona.<br />
The species appears to be widesp<strong>re</strong>ad in the<br />
world but not cosmopolitan. Düll (1984), for example,<br />
indicated <strong>re</strong>ported locations throughout all <strong>of</strong> North and<br />
South America and Africa, Asia Minor and East Asia. It<br />
has a bipolar distribution and may be widesp<strong>re</strong>ad in the<br />
southern hemisphe<strong>re</strong> as well as the northern, however<br />
some caution is advisable due to the occur<strong>re</strong>nce <strong>of</strong><br />
similar taxa with diffe<strong>re</strong>nt sexuality (see discussion<br />
below). Certain absences <strong>of</strong> stations, or rarities seem<br />
curious, such as its absence from the British flora,<br />
although the climate the<strong>re</strong> dosen't seem to be an<br />
inhibiting factor when North American stations can be<br />
found as far north as Quebec. The species is virtually<br />
absent from Central Europe (Braunmiller et al. 1971;<br />
Düll & Meinunger 1989). In the former Soviet Union it<br />
is only <strong>re</strong>ported from European states and the Caucasus<br />
<strong>re</strong>gion, leaving the enti<strong>re</strong> eastern <strong>re</strong>gion without a<br />
<strong>re</strong>p<strong>re</strong>sentation (Ignatov & Afonina 1992).<br />
The epithet perhaps <strong>re</strong>fers to the short stem<br />
<strong>re</strong>sulting in a typically squat, rosulate rather than<br />
elongated habit that is mo<strong>re</strong> characteristic <strong>of</strong> other<br />
species in the genus. Tortella humilis is <strong>re</strong>cognized by<br />
its short stems with leaves in dense, stacked whorls in<br />
obscu<strong>re</strong> annual innovations subtended by tiny proximal<br />
leaves, by the <strong>re</strong>latively broad to occasionally narrowly<br />
acute, plane, non-cucullate to concave leaf apices, small<br />
and obscu<strong>re</strong> cells, and autoicous inflo<strong>re</strong>scences.<br />
In cross section, the costa diminishes in size<br />
toward the leaf tip: sectioning distally along the leaf, the<br />
epidermal layer first disappears, leaving up to two<br />
ste<strong>re</strong>id cells in width exposed. In some instances at the<br />
ext<strong>re</strong>me apex, even the ste<strong>re</strong>id layer disappears leaving<br />
the guide cells exposed. The apices <strong>of</strong> the leaves usually<br />
seem to twist at the apex so that one lamina lies flat and<br />
the other extends upwards. This is because one side <strong>of</strong><br />
the lamina is usually somewhat shorter than the other,<br />
with the shorter side angling toward the vertical.<br />
The leaves <strong>of</strong> Tortella humilis, together with<br />
those <strong>of</strong> unambiguous specimens <strong>of</strong> T. arctica, younger<br />
leaves <strong>of</strong> T. flavovi<strong>re</strong>ns and those <strong>of</strong> European T. nitida,<br />
a<strong>re</strong> notable by the gradual rather than abrupt transition<br />
<strong>of</strong> proximal cells to the distal laminal ones in addition to<br />
the marginal thin-walled cells that extend up the leaf<br />
margins, forming a U-shape to the proximal <strong>re</strong>gion,<br />
rather than the distinctive tortelloid V-shape. This<br />
6<br />
characteristic will permit easy confusion <strong>of</strong><br />
inf<strong>re</strong>quently sterile forms <strong>of</strong> Tortella humilis with<br />
Trichostomum tenuirost<strong>re</strong> (Hook. & Tayl.) Lindb. The<br />
well-developed peristome—elongate and conspicuously<br />
twisted—will distinguish Tortella humilis from<br />
specimens <strong>of</strong> T. flavovi<strong>re</strong>ns and Trichostomum species,<br />
whose peristomes a<strong>re</strong> either not or little twisted, or a<strong>re</strong><br />
rudimentary. Any specimen without fruit is unlikely to<br />
be Tortella humilis: if the<strong>re</strong> is no V-shape in any <strong>of</strong> the<br />
leaves on the stem, and if the<strong>re</strong> is the slightest hint <strong>of</strong><br />
marginal scalloping <strong>of</strong> the lamina and lamina fragility,<br />
the specimen is probably Trichostomum tenuirost<strong>re</strong>; if<br />
the sterile specimen occurs on coastal beaches in the<br />
southeastern United States, it is most likely Tortella<br />
flavovi<strong>re</strong>ns.<br />
In a<strong>re</strong>as whe<strong>re</strong> the ranges overlap, the leaves <strong>of</strong><br />
fertilized perichatia <strong>of</strong> the somewhat similar Tortella<br />
inclinata a<strong>re</strong> stiff, e<strong>re</strong>ct, narrowly lanceolate-subulate<br />
and have long-excur<strong>re</strong>nt costae, whe<strong>re</strong>as those <strong>of</strong> T.<br />
humilis a<strong>re</strong> little diffe<strong>re</strong>ntiated from the stem leaves.<br />
Tortella inclinata has a narrow groove <strong>of</strong> elongate,<br />
smooth-walled cells on the adaxial surface <strong>of</strong> the costa<br />
throughout the leaf and has no stem central strand,<br />
whe<strong>re</strong>as T. humilis has quadrate, papillose cells on the<br />
adaxial surface <strong>of</strong> the costa in the mid-leaf <strong>re</strong>gion and a<br />
well-developed central strand.<br />
Because the cells on the adaxial surface <strong>of</strong> the<br />
costa a<strong>re</strong> similar in shape and size to the laminal cells,<br />
and because the leaf base is <strong>of</strong>ten narrow (the leaf<br />
widest in the middle), and because the<strong>re</strong> is a stem<br />
central strand, the<strong>re</strong> is a superficial <strong>re</strong>semblance to<br />
Hyophila involuta (Hook.) Jaeg. & Sauerb.. This species<br />
typically differs by dentate leaf apices, horned<br />
propagula in the leaf axils and laminal cells in section<br />
bulging higher on the adaxial surface than the abaxial. It<br />
has no peristome nor does it fruit in our a<strong>re</strong>a. Plaubelia<br />
sp<strong>re</strong>ngelii (Schwaegr.) Zand., which is dioicous, lacks a<br />
well-developed adaxial ste<strong>re</strong>id band and has e<strong>re</strong>ct<br />
peristome teeth.<br />
Plants <strong>of</strong> Tortella humilis a<strong>re</strong> <strong>of</strong>ten confused<br />
with Barbula unguiculata Hedw., which differs most<br />
<strong>re</strong>adily in the <strong>re</strong>curvatu<strong>re</strong> <strong>of</strong> the proximal leaf margin<br />
and its dioicous condition. Crum and Anderson (1981)<br />
describe and illustrate the ra<strong>re</strong> species Trichostomum<br />
spirale Grout from the G<strong>re</strong>at Lakes <strong>re</strong>gion (Ontario,<br />
Wisconsin, Minnesota) that, like Tortella humilis, is a<br />
nearly stemless plant with gradually diffe<strong>re</strong>ntiated<br />
proximal cells and a similar leaf shape. It also has<br />
stalked perigonial buds and is autoicous, unlike the<br />
usual dioicous condition <strong>of</strong> the genus Trichostomum. It<br />
may be distinguished by the peristome teeth which a<strong>re</strong><br />
said to be short, e<strong>re</strong>ct and smooth or marked with spiral<br />
lines rather than spiculose papillae, the latter<br />
characteristic <strong>of</strong> peristomes <strong>of</strong> the genus Tortella.<br />
Two specimens seen from Mexico that<br />
conform to Tortella humilis (see Zander 1994d) in most<br />
<strong>re</strong>spects we<strong>re</strong> both autoicous and paroicous on the same<br />
stem, that is, they had stalked perigonial buds as well as<br />
robust antheridia in the axils <strong>of</strong> the distal stem leaves.<br />
Carl Müller (1878–79: 339–340) originally described
Tortella pseudocespitosa (C. Müll.) Broth. as<br />
androgynous, with antheridia naked in the axils <strong>of</strong> the<br />
distal, fertile (i.e perichaetial) leaves or included in<br />
small-leaved, very short-stalked gemmulae. This plant,<br />
known only from Argentina and the southern part <strong>of</strong><br />
South America, has two other varieties that, by their<br />
names—var. pungens (C. Müll.) Par. probably <strong>re</strong>ferring<br />
to an acute or acuminate-leaved plant, and var.<br />
brachybasis (C. Müll.) Par., to shorter, broader-leaved<br />
plants—indicates a plasticity in the leaf shape not unlike<br />
that attributed to T. humilis (see discussion below) in<br />
America north <strong>of</strong> Mexico. These taxa may be<br />
synonymous, adopting the mo<strong>re</strong> complex (paroicous in<br />
addition to autoicous) condition in the southern<br />
latitudes. That an Argentinian species might occur in<br />
Mexico, however, would not be surprising. Cursory<br />
examination <strong>of</strong> an isotype <strong>of</strong> T. pseudocaespitosa (NY)<br />
shows that the<strong>re</strong> is some promise in this speculation.<br />
Bryoerythrophyllum <strong>re</strong>curvirostrum (Hedw.) Chen var.<br />
<strong>re</strong>curvirostrum may be similar in that in North America<br />
north <strong>of</strong> Mexico the species is synoicous or paroicous.<br />
In Mexico and Guatemala, however, the var. aeneum<br />
(C. Müll.) Zand. is "Dioicous or polygamous (with at<br />
least some gemmiform perigonia in addition to<br />
synoicous and paroicous inflo<strong>re</strong>scences" (Zander<br />
1994a).<br />
After many specimens <strong>of</strong> Tortella humilis we<strong>re</strong><br />
examined, the<strong>re</strong> at first appea<strong>re</strong>d to be two approximate<br />
facies in the floral a<strong>re</strong>a: one with stems short-rosulate,<br />
tomentose, leaf apices broadly acute to obtuse,<br />
occasionally broadest above the base to oblong from an<br />
appa<strong>re</strong>ntly narrower, sub-clasping base, with proximal<br />
cells in an indistinct or shallow "U" shape, gradually set<br />
<strong>of</strong>f from laminal cells, the leaves short, 3–5 (–7):1. Dry<br />
plant habits we<strong>re</strong> crisped, with leaf tips curved under.<br />
This is the typical facies nearly universally <strong>re</strong>cognized<br />
in floristic manuals.<br />
The other facies, best seen in specimens from<br />
Texas, British Columbia and Ontario, have elongate<br />
(not rosulate) stems in obvious annual whorls,<br />
tomentum generally absent except for coarse radicles at<br />
the base, leaf apices narrowly acute with leaves broadest<br />
toward the base, proximal cells higher in a mo<strong>re</strong> distinct<br />
and generically typical V-shape, mo<strong>re</strong> abruptly set <strong>of</strong>f<br />
from the laminal cells, the leaves long-lanceolate, <strong>of</strong>ten<br />
to 4 mm long, in some cases the shape approximating<br />
that <strong>of</strong> Tortella tortuosa, 7–9:1. These longer, gracile<br />
forms have somewhat longer setae and capsules. Dry<br />
plants <strong>of</strong> this second morphotype have most leaves<br />
e<strong>re</strong>ct-sp<strong>re</strong>ading. This facies was identified by Zander<br />
(1994d) for Mexico with T. japonica (Besch.) Broth., an<br />
autoicous species p<strong>re</strong>viously known only from Japan<br />
<strong>re</strong>sembling T. humilis but with lanceolate to narrowlanceolate<br />
leaves (Saito 1975). The Mexican specimens<br />
examined by Zander we<strong>re</strong> <strong>re</strong>-examined for this paper,<br />
and all specimens fell within the morphologic amplitude<br />
<strong>of</strong> the Texas, British Columbia and Ontario specimens,<br />
and hence can be named T. humilis.<br />
The variation in facies <strong>of</strong> T. humilis seems to<br />
cor<strong>re</strong>late in a bull's-eye fashion with the shorter facies in<br />
7<br />
the center <strong>of</strong> the North American range for the species<br />
and the elongate ones at the outer boundaries,<br />
especially, by numbers <strong>of</strong> herbarium specimens, in the<br />
south. This variation can be detected in collections from<br />
northern herbaria, such as MICH, in the center <strong>of</strong> the<br />
range whe<strong>re</strong> stenotypic plants a<strong>re</strong> typical, and those<br />
from southern herbaria, such as DUKE, whose<br />
specimens tend to be mo<strong>re</strong> elongate overall. The pattern<br />
<strong>of</strong> variation <strong>of</strong> Trichostomum tenuirost<strong>re</strong> may be similar<br />
or identical (Crum & Anderson 1958).<br />
Tortella humilis was said not to occur in Japan<br />
(Saito 1975; Noguchi 1988). Thirty-nine specimens<br />
from TNS determined as Tortella japonica proved to be<br />
either <strong>of</strong> two taxa: T. humilis or Trichostomum<br />
tenuirost<strong>re</strong>. Material <strong>of</strong> Tortella japonica, including the<br />
type specimen borrowed from PC, was indistinguishable<br />
from the elongate American facies <strong>of</strong> T. humilis in the<br />
general elongation <strong>of</strong> the leaves, becoming narrower<br />
and mo<strong>re</strong> acute in interior perichaetial leaves. Since the<br />
typical facies <strong>of</strong> T. humilis grades into this variant in<br />
North America, especially in Mexico, Texas, British<br />
Columbia and Ontario, that is, on the margins <strong>of</strong> the<br />
range <strong>of</strong> the species, and since the<strong>re</strong> is no other<br />
distinguishing characteristic, T. japonica is conside<strong>re</strong>d<br />
he<strong>re</strong> a new synonym <strong>of</strong> T. humilis. Populations <strong>of</strong> T.<br />
humilis in Japan may be interp<strong>re</strong>ted to occur on the<br />
margin <strong>of</strong> the range <strong>of</strong> the mo<strong>re</strong> typical facies <strong>of</strong> the<br />
species in continental Asia, as described for China, for<br />
example, by Chen (1941). No short-leaved forms <strong>of</strong> T.<br />
humilis we<strong>re</strong> seen from Japan.<br />
In 1965, the number <strong>of</strong> Tortella species in<br />
Japan was eight, and Tortella humilis was conside<strong>re</strong>d to<br />
be one <strong>of</strong> them (Sch<strong>of</strong>ield 1965). Sch<strong>of</strong>ield also cited<br />
the specimen (Sch<strong>of</strong>ield and Boas 18192, UBC)<br />
discussed from British Columbia in the p<strong>re</strong>sent<br />
t<strong>re</strong>atment as a form approaching published descriptions<br />
<strong>of</strong> Tortella japonica. It was the only collection from<br />
British Columbia in 1965 and appa<strong>re</strong>ntly still is to date.<br />
Saito (1975), however, did not include Tortella humilis<br />
in his pottiaceous flora <strong>of</strong> Japan, that is, he excluded it<br />
from occurring in that country. Saito <strong>re</strong>cognized only<br />
th<strong>re</strong>e species: Tortella tortuosa, T. fragilis and T.<br />
japonica. Tortella japonica was distinguished from T.<br />
humilis by the "lanceolate to linear-lanceolate leaves<br />
with a sharply pointed, acute apex" <strong>of</strong> the former<br />
species and indicated that that species had rhizoids<br />
<strong>re</strong>stricted to the base <strong>of</strong> the stem, i.e., that the stem was<br />
not tomentose. The type <strong>of</strong> T. japonica, however, had<br />
one <strong>of</strong> the most robust habits I examined, and it was<br />
densely tomentose with a rufous tomentum. Further<br />
specimens examined from Japan we<strong>re</strong> variably<br />
tomentose and since the natu<strong>re</strong> <strong>of</strong> the substrate does not<br />
appear to be a factor, perhaps this variation is due to the<br />
inc<strong>re</strong>ased age or size <strong>of</strong> the plant.<br />
Although Noguchi (1988) described distinctive<br />
inner perichaetial leaves for T. japonica, diffe<strong>re</strong>ntiated<br />
from those <strong>of</strong> the vegetative leaves as a subulate<br />
acumen above an oblong base. This character could not<br />
be well demonstrated in specimens examined from<br />
Japan, nor in the type specimen. The<strong>re</strong> may be one or
two narrower inner perichaetial leaves whose laminae<br />
a<strong>re</strong> only somewhat narrower in the distal <strong>re</strong>gion, this<br />
character exaggerated by the p<strong>re</strong>sence <strong>of</strong> a longer mucro<br />
on most <strong>of</strong> the leaves <strong>of</strong> the elongate forms and by<br />
incurved distal margins. Elongate forms <strong>of</strong> T. humilis in<br />
North America sha<strong>re</strong> this characteristic as well.<br />
Occasionally the inner perichaetial leaves may be rather<br />
abruptly contracted above a mo<strong>re</strong> or less sheathing base,<br />
forming a narrow limb as in some leaves <strong>of</strong> the type <strong>of</strong><br />
T. japonica. However, this may also be seen in<br />
specimens <strong>of</strong> the short-leaved forms <strong>of</strong> T. humilis in<br />
North America as well and is conside<strong>re</strong>d he<strong>re</strong> to be part<br />
<strong>of</strong> the normal variation in the species. The perichaetial<br />
leaves <strong>of</strong> T. humilis in either long or short forms a<strong>re</strong><br />
conside<strong>re</strong>d he<strong>re</strong> to be undiffe<strong>re</strong>ntiated. Diffe<strong>re</strong>ntiated<br />
perichaetial leaves in the p<strong>re</strong>sent paper a<strong>re</strong> diffe<strong>re</strong>nt<br />
almost in kind from the stem leaves: primarily with a<br />
long, naked extension <strong>of</strong> the costa into an awn, such as<br />
occurs in T. tortuosa, T. inclinata var. inclinata, T.<br />
alpicola and T. fragilis.<br />
Saito also did not mention that the proximal<br />
cells interior to the proximal marginal cells gradually<br />
intergrade with the distal laminal cells, as is<br />
characteristic <strong>of</strong> Tortella humilis. In the elongated forms<br />
<strong>of</strong> North American material, especially in leaves toward<br />
the stem apex, the longer leaves have a mo<strong>re</strong><br />
distinctively V-shaped diffe<strong>re</strong>ntiation <strong>of</strong> the proximal<br />
cells. This is true in the longest leaves <strong>of</strong> intermediate<br />
American forms, such as in the outer perichaetial leaves,<br />
whe<strong>re</strong>as the intergradation is less distinct in shorter<br />
leaves, and me<strong>re</strong>ly U-shaped in very short-leaved<br />
material. Unfortunately, the variable Trichostomum<br />
tenuirost<strong>re</strong> also has a U-shaped diffe<strong>re</strong>ntiated proximal<br />
<strong>re</strong>gion very similar to specimens <strong>of</strong> both Tortella<br />
japonica and T. humilis, and, as in Saito's illustration,<br />
the diffe<strong>re</strong>ntiated proximal cells <strong>of</strong> Trichostomum<br />
tenuirost<strong>re</strong> do extend up the margins in various deg<strong>re</strong>es,<br />
just as in the genus Tortella. While Tortella japonica<br />
may <strong>of</strong>ten be tomentose, Trichostomum tenuirost<strong>re</strong> is<br />
never so.<br />
It is possible that descriptions <strong>of</strong> Tortella<br />
japonica by Saito (1975) and Noguchi (1988) include to<br />
some deg<strong>re</strong>e the characteristics <strong>of</strong> Trichostomum<br />
tenuirost<strong>re</strong> (= Oxystegus cylindricus (Brid.) Hilp.), a<br />
species which may be nearly indistinguishable from<br />
sterile specimens <strong>of</strong> the elongate-leaved Tortella<br />
humilis, and whose ranges and substrates overlap. In<br />
fertile specimens the best distinction is in the nearly<br />
always demonstrable autoicous bud in the latter species<br />
and its long-twisted peristomes in fruiting material. The<br />
former species is dioicous with comparatively shorte<strong>re</strong>ct<br />
teeth. In fact, the leaf shape <strong>of</strong> the plant illustrated<br />
for Trichostomum tenuirost<strong>re</strong> by Saito (1975) <strong>re</strong>sembles<br />
closely that <strong>of</strong> typical Tortella humilis, complete with<br />
the indication <strong>of</strong> the "U" shape <strong>of</strong> diffe<strong>re</strong>ntiated<br />
proximal cells. Trichostomum tenuirost<strong>re</strong> also has a<br />
mo<strong>re</strong> elongate stem (to 15 mm), usually mo<strong>re</strong> than twice<br />
the length <strong>of</strong> the stemless to short-stemmed Tortella<br />
japonica (to 7 mm).<br />
8<br />
Note that, although Saito (1975) indicated<br />
that Tortella japonica has a stem central strand and that<br />
Trichostomum tenuirost<strong>re</strong> does not, the latter species<br />
does, in many cases, have one, both in the Japanese<br />
material examined and as attributed to that species in<br />
the United States (Flowers 1973) and in Europe (Hilpert<br />
1933).<br />
When both species a<strong>re</strong> sterile, they may be<br />
distinguished by the <strong>re</strong>latively shorter stem <strong>of</strong> Tortella<br />
humilis (to 7 mm), its rosulate habit, its variable<br />
tomentum and its leaf edge firm and orderly (<strong>re</strong>gular),<br />
as opposed to the mo<strong>re</strong> elongate stem <strong>of</strong> Trichostomum<br />
tenuirost<strong>re</strong> (to 15 mm), the leaves mo<strong>re</strong> loosely<br />
disposed on the stem, its lack <strong>of</strong> tomentum and its leaf<br />
edge <strong>of</strong>ten showing a scalloping or lobing edge<br />
indicating zones <strong>of</strong> weakness; the<strong>re</strong> is g<strong>re</strong>ater fragility<br />
<strong>of</strong> the leaf lamina and occasional obscu<strong>re</strong> and distant<br />
marginal teeth in the distal leaf <strong>re</strong>gion. Also a<br />
distinctive V-shaped proximal cell <strong>re</strong>gion <strong>of</strong> Tortella<br />
humilis may <strong>of</strong>ten be successfully found on the largest<br />
leaves, whe<strong>re</strong>as in Trichostomum tenuirost<strong>re</strong> this will<br />
not occur.<br />
The type <strong>of</strong> Tortella japonica <strong>re</strong>p<strong>re</strong>sents a large<br />
statu<strong>re</strong> that even the ordinary <strong>re</strong>p<strong>re</strong>sentative specimens<br />
in Japan do not approach, yet the type material (at PC)<br />
has the same leaf shape as ordinary North American<br />
material. Such large statu<strong>re</strong> was duplicated in a<br />
specimen from Ontario, Canada from the north sho<strong>re</strong> <strong>of</strong><br />
Lake Huron, possessing a proliferation <strong>of</strong> branches, four<br />
<strong>of</strong> which supported fertile perichaetia with a long stem<br />
to 7 mm, the longest among variants on the margins <strong>of</strong><br />
the North American floral distribution.<br />
In Zander's (1994d) description <strong>of</strong> Tortella<br />
japonica from Mexico, he noted the "shiny upper part <strong>of</strong><br />
the costa, owing to smooth, elongate cells on the ventral<br />
surface" contributed to the distinctiveness <strong>of</strong> the<br />
Mexican specimens examined. However, he also<br />
described the plants as having a "costa cove<strong>re</strong>d on the<br />
adaxial surface in the middle <strong>of</strong> the leaf by quadrate,<br />
papillose cells." In typical short-leaved Tortella humilis,<br />
the quadrate cells on the adaxial surface <strong>of</strong> the costa<br />
disappear toward the apex <strong>of</strong> the leaf—but this is<br />
inconspicuous. In leaves significantly mo<strong>re</strong> elongate,<br />
this <strong>re</strong>gion <strong>of</strong> elongate, smooth cells is also longer and<br />
mo<strong>re</strong> conspicuous. The same comparison may be made<br />
between short and very long leaves <strong>of</strong> Tortella tortuosa.<br />
Clearly Tortella humilis, a widesp<strong>re</strong>ad species<br />
in the Northern and possibly Southern Hemisphe<strong>re</strong>,<br />
shows a plasticity not p<strong>re</strong>viously <strong>re</strong>cognized. In North<br />
America, it grades from short, broad plants in the<br />
northcentral and eastern distribution, becoming mo<strong>re</strong><br />
gracile on its margins, especially to the south. Indeed,<br />
upon <strong>re</strong>view <strong>of</strong> examples at BUF used by Zander for the<br />
Moss Flora <strong>of</strong> Mexico, nearly all <strong>of</strong> the Mexican<br />
material <strong>of</strong> Tortella humilis is a "Tortella japonica"<br />
facies similar to plants from Texas and the southern<br />
American states. All other material seen in a small<br />
sample <strong>of</strong> Mexican specimens at BUF, <strong>re</strong>p<strong>re</strong>sents<br />
minute plants that a<strong>re</strong> sterile, or a<strong>re</strong> possibly not<br />
satisfactorily named.
The single specimen <strong>re</strong>ported for New<br />
Brunswick (Albert Co.) by I<strong>re</strong>land (1982) is<br />
Trichostomum tenuirost<strong>re</strong>, having no central strand,<br />
fragile leaves, several leaves with thick-walled proximal<br />
marginal cells, dioicous (perichaetiate with no autoicous<br />
buds) and is hence excluded from the province. The<br />
specimen from Nova Scotia (I<strong>re</strong>land 1982) <strong>re</strong>ported<br />
from Inverness County is Hymenostylium<br />
<strong>re</strong>curvirostrum (Hedw.) Dix.<br />
2. TORTELLA FLAVOVIRENS Plate 2<br />
Tortella flavovi<strong>re</strong>ns (Bruch ex F. Müll.) Broth. in E. &<br />
P., Nat. Pfl. 1(3): 397. 1902.<br />
Trichostomum flavovi<strong>re</strong>ns Bruch ex F. Müll.,<br />
Flora 12(1): 404. 1829.<br />
Plants in loose or dense tufts, usually pale delicate<br />
yellow above, yellow-brown below, elongate, not<br />
rosulate, annual whorls <strong>of</strong>ten evident. Stems 0.3–1.0 cm<br />
high, hyalodermis large, sclerodermis inconspicuous,<br />
cells <strong>of</strong> central cylinder thick-walled, central strand<br />
p<strong>re</strong>sent, without tomentum, rhizoids thick and sparse at<br />
the base. Stem leaves loosely foliose, gradually<br />
somewhat larger and mo<strong>re</strong> crowded toward the stem<br />
tips, loosely to typically tightly incurled-contorted<br />
around the stem when dry, sube<strong>re</strong>ct to sp<strong>re</strong>ading when<br />
moist, oblong-ovate or ovate-lanceolate, strongly<br />
keeled-concave distally or broadly channeled across the<br />
leaf proximally, 2–3.5 mm long; base somewhat<br />
broader, elliptical; margins e<strong>re</strong>ct to incurved-involute,<br />
especially toward the apex, not or somewhat undulate,<br />
limb gradually or quickly narrowed; apex obtuse,<br />
subcucullate; costa percur<strong>re</strong>nt or short excur<strong>re</strong>nt, ra<strong>re</strong>ly<br />
disappearing befo<strong>re</strong> the apex on some leaves, adaxial<br />
epidermal cells papillose-quadrate to short-<strong>re</strong>ctangular<br />
at midleaf, f<strong>re</strong>quently disappearing, showing smooth<br />
and narrowly elongate (6:1) ste<strong>re</strong>id adaxial cells at the<br />
ext<strong>re</strong>me apex; in cross section adaxial epidermis <strong>of</strong><br />
quadrate, papillose cells typically p<strong>re</strong>sent, occasionally<br />
absent in patches toward the apex, adaxial and abaxial<br />
ste<strong>re</strong>id bands and one row <strong>of</strong> guide cells p<strong>re</strong>sent;<br />
proximal laminal cells in larger leaves rather abruptly<br />
diffe<strong>re</strong>ntiated from distal cells, yellow-hyaline and<br />
nearly concolorous with the distal lamina, long<strong>re</strong>ctangular,<br />
8(–9):1, laxly thin-walled, gradually<br />
papillose, in some shorter leaves, however, proximal<br />
cells gradually diffe<strong>re</strong>ntiated with a marginal border <strong>of</strong><br />
elongate thin-walled cells; marginal angle <strong>of</strong><br />
diffe<strong>re</strong>ntiated proximal cells generally steep; distal<br />
laminal cells 10–12(–14) µm wide. Asexual<br />
<strong>re</strong>production: modifications for asexual <strong>re</strong>production<br />
none. Sexual condition dioicous. Perigonia not seen.<br />
Perichaetial leaves little diffe<strong>re</strong>ntiated, outer leaves<br />
somewhat longer, inner shorter than the stem leaves,<br />
without marginal differtiation. Seta <strong>re</strong>d, sometimes<br />
vivid below, paler above, 1.1–1.3 cm long. Capsule<br />
1.8–2.2 mm long, <strong>of</strong>ten mo<strong>re</strong> or less wrinkled-plicate<br />
when dry and empty, mouth rimmed with <strong>re</strong>d; annulus<br />
none; operculum 0.75–1 mm long, nearly subulate when<br />
9<br />
young, mo<strong>re</strong> broadly long-conic just befo<strong>re</strong><br />
dehiscence; peristome teeth <strong>re</strong>latively short, to 0.5 mm<br />
long, straight or obliquely inclined and slightly twisted,<br />
especially when newly deoperculate. Calyptra<br />
cucullate, narrow, the split twisted in conformity with<br />
the spiralling <strong>of</strong> its cells. Spo<strong>re</strong>s (10–)12(–14) µm, from<br />
the single capsule seen coarsely papillose, papillae small<br />
and somewhat ir<strong>re</strong>gular in size and distribution, but not<br />
punctate or fine as in the literatu<strong>re</strong>.<br />
Seldom collected in fruiting condition. Spo<strong>re</strong>s<br />
matu<strong>re</strong> in mid to late spring.<br />
Inf<strong>re</strong>quently collected, this salt-tolerant plant<br />
grows near sea level just above the tidal zone in<br />
saltwater spray on coastal beaches and <strong>of</strong>fsho<strong>re</strong> islands<br />
<strong>of</strong> the southeastern United States: exposed sites on<br />
sandy soil, coquina, among dunes, juniper scrub, lawns<br />
and other grassy, weedy a<strong>re</strong>as, damp conc<strong>re</strong>te, mortar in<br />
old forts, and is never found in wooded a<strong>re</strong>as or on<br />
humic material, such as the bark <strong>of</strong> t<strong>re</strong>es. Ala., Fla., Ga.,<br />
N.C., S.C., Tex.; Bermuda, in Europe confined to ocean<br />
and Mediterranean coasts, Macaronesia, Syria, n Africa,<br />
New Zealand.<br />
Herbaria examined: BUF, CANM, COLO,<br />
DUKE, FLAS, MICH, MO, NY, UBC.<br />
Its affinity for sandy stations associated with<br />
water, together with the cucullate leaves is <strong>re</strong>miniscent<br />
<strong>of</strong> Tortella inclinata <strong>of</strong> northern <strong>re</strong>gions. Perhaps<br />
because <strong>of</strong> the Gulf St<strong>re</strong>am in the Atlantic Ocean, the<br />
ranges <strong>of</strong> T. flavovi<strong>re</strong>ns and T. inclinata overlap in<br />
England and the oceanic coasts <strong>of</strong> western Europe,<br />
causing some difficulty in identification the<strong>re</strong>.<br />
In North America, populations <strong>of</strong> these two<br />
species a<strong>re</strong> widely separated, that <strong>of</strong> Tortella inclinata<br />
following the southern edge <strong>of</strong> furthest <strong>re</strong>cent glaciation<br />
(Miller 1976). The p<strong>re</strong>sent distribution <strong>of</strong> that species<br />
seems to be closely bound with continental glacial<br />
history. T. flavovi<strong>re</strong>ns may be expected to occur on<br />
beaches associated with warm oceanic cur<strong>re</strong>nts. Coasts<br />
associated with cold ocean cur<strong>re</strong>nts, such as those <strong>of</strong>f<br />
the northern coast <strong>of</strong> Pacific North America, might<br />
p<strong>re</strong>clude the occur<strong>re</strong>nce <strong>of</strong> the species the<strong>re</strong>.<br />
The range limits as p<strong>re</strong>sently known in the<br />
United States may <strong>re</strong>flect mo<strong>re</strong> the limits <strong>of</strong> <strong>re</strong>gional<br />
collectors than that <strong>of</strong> the species itself: it should be<br />
found in the contiguous coast <strong>of</strong> Mexico and in the<br />
islands <strong>of</strong> the Caribbean generally, and possibly also in<br />
states to the north <strong>of</strong> North Carolina whose coasts a<strong>re</strong><br />
warmed by the Gulf St<strong>re</strong>am. The species was not<br />
<strong>re</strong>ported from the beaches <strong>of</strong> Puerto Rico and the Virgin<br />
Islands (Crum & Stee<strong>re</strong> 1957), Jamaica (Crum &<br />
Bartram 1958) or Mexico (Zander 1994d). Many <strong>of</strong> the<br />
specimens collected in the United States we<strong>re</strong><br />
concentrated around the city <strong>of</strong> St. Augustine, Florida.<br />
Sampling <strong>of</strong> additional populations in the Atlantic-<br />
Caribbean a<strong>re</strong>a may <strong>re</strong>veal mo<strong>re</strong> details about this<br />
species.<br />
One possibility to consider is that the species<br />
has been <strong>re</strong>cently introduced on the American coast and<br />
is sp<strong>re</strong>ading. Rubers (1973) <strong>re</strong>ported that the variety<br />
glariecola (Christ.) Crundw. & Nyh. is quite common
throughout the seacoast <strong>of</strong> the Netherlands, especially<br />
between Voorne and Schoorl, whe<strong>re</strong>as that <strong>of</strong> the var.<br />
flavovi<strong>re</strong>ns is known only from four localities. In the<br />
Netherlands, the leaf cell size <strong>of</strong> var. flavovi<strong>re</strong>ns is 8–10<br />
µm whe<strong>re</strong>as that <strong>of</strong> var. glariecola is much larger: 10–<br />
14 µm. Based on a <strong>re</strong>port by Townsend (1965) <strong>of</strong><br />
sporophyte material <strong>of</strong> the var. glariecola found on the<br />
island <strong>of</strong> Cyprus, the<strong>re</strong> is also an appa<strong>re</strong>nt diffe<strong>re</strong>nt in<br />
the spo<strong>re</strong> size (Rubers 1973). That American<br />
populations <strong>re</strong>p<strong>re</strong>sent only the var. flavovi<strong>re</strong>ns, even<br />
though the leaf cells a<strong>re</strong> on average larger (to 12 µm<br />
with some cells <strong>re</strong>aching 14 µm), may indicate that the<br />
American populations a<strong>re</strong> depauperate. The issue<br />
<strong>re</strong>qui<strong>re</strong>s further study.<br />
Braunmiller et al. (1971) state that the center <strong>of</strong><br />
dispersal in Europe is the Mediterranean <strong>re</strong>gion whe<strong>re</strong><br />
the species is broadly distributed and common, with<br />
scatte<strong>re</strong>d outposts along the western European coast to<br />
Denmark and England.<br />
The species forms a suite with other<br />
Mediterranean Tortellas: T. inflexa and T. nitida. These<br />
authors seem to indicate that only in the northwest <strong>of</strong><br />
Europe does the<strong>re</strong> occur two varieties <strong>of</strong> Tortella<br />
flavovi<strong>re</strong>ns, the typical one and the var. glariecola.<br />
They also suggest that the only German <strong>re</strong>ports <strong>of</strong> T.<br />
flavovi<strong>re</strong>ns a<strong>re</strong> those <strong>of</strong> the typical variety.<br />
Stations outside <strong>of</strong> North America a<strong>re</strong> based on<br />
published <strong>re</strong>ports. The species has such a large <strong>re</strong>ported<br />
world distribution, in addition to the Atlantic and the<br />
Mediterranean, that one might even expect it on tropical<br />
or subtropical coasts <strong>of</strong> Pacific North America (A.C.<br />
Crundwell, pers.comm.) unless cold ocean cur<strong>re</strong>nts<br />
p<strong>re</strong>clude this.<br />
In the United States, all specimens <strong>of</strong> Tortella<br />
flavovi<strong>re</strong>ns that we<strong>re</strong> inland from coastal habitats we<strong>re</strong><br />
<strong>re</strong>determined to be some other species: T humilis most<br />
f<strong>re</strong>quently, Trichostomum crispulum and Weissia spp.<br />
The fact that Tortella flavovi<strong>re</strong>ns is salt-tolerant may be<br />
helpful in excluding taxa, such as T. inclinata, from<br />
similar habitats. In Europe, the range <strong>of</strong> T. flavovi<strong>re</strong>ns is<br />
thought to overlap that <strong>of</strong> T. inclinata. However, if T.<br />
flavovi<strong>re</strong>ns is an obligate halophyte and T. inclinata is<br />
intolerant <strong>of</strong> salty conditions, the ranges may be me<strong>re</strong>ly<br />
contiguous.<br />
Crum and Anderson (1981: 306) <strong>re</strong>ported that<br />
"Nyholm [1956: 137] included in the species'[sic] range<br />
Macaronesia, North Africa, the Middle East, China, and<br />
Japan." Noguchi (1988), however, did not include it in<br />
the moss flora <strong>of</strong> Japan, nor did Redfearn (1993) for<br />
China. Fife (1995), however, <strong>re</strong>ported it from New<br />
Zealand whe<strong>re</strong> it had been known as T. rubripes (Mitt.)<br />
Broth., a species p<strong>re</strong>viously thought to be endemic to<br />
New Zealand. It was described by Sainsbury (1955) as<br />
an "exclusively...maritime plant" which "can properly<br />
be described as a halophyte, its station being at<br />
practically the edge <strong>of</strong> the sea. It is widely distributed<br />
on the coast in the Auckland District, and appears he<strong>re</strong><br />
and the<strong>re</strong> as far south as the Mahina Peninsula, Hawke's<br />
Bay."<br />
10<br />
The characteristic pale yellow leaves (versus<br />
the mo<strong>re</strong> opaque and sordid yellow- or bright g<strong>re</strong>en <strong>of</strong><br />
T. humilis and T. inclinata) is indicated in the epithet.<br />
Dixon (1924) cited Limpricht (1890) as diffe<strong>re</strong>ntiating<br />
between Tortella flavovi<strong>re</strong>ns and T. inclinata, whose<br />
ranges overlap in G<strong>re</strong>at Britain, by the p<strong>re</strong>sence <strong>of</strong> a<br />
stem central strand in the former, and its absence in the<br />
latter. "In undoubted [Tortella] flavovi<strong>re</strong>ns from our<br />
coasts, however, I find the central strand enti<strong>re</strong>ly absent,<br />
and the stem in section exactly similar to that <strong>of</strong> [T.]<br />
inclinata" (Dixon 1924). Smith (1978) stated that T.<br />
flavovi<strong>re</strong>ns "<strong>of</strong>ten" has a stem central strand. In material<br />
examined from the southeastern United States, the stems<br />
<strong>re</strong>gularly had a distinct central strand.<br />
The leaf cross section <strong>of</strong> Tortella flavovi<strong>re</strong>ns<br />
exhibits an adaxial layer <strong>of</strong> quadrate, papillose cells<br />
across its surface throughout the leaf length excepting<br />
the proximal <strong>re</strong>gion and the ext<strong>re</strong>me apex. In section,<br />
the leaf is keeled beside the costa, then widens broadly<br />
out befo<strong>re</strong> widely curving inwards in the shape <strong>of</strong> a<br />
caliper or tongs. The leaf cross section <strong>of</strong> T. humilis is<br />
generally flat with the margins shortly and slightly e<strong>re</strong>ct<br />
or somewhat incurved, becoming mo<strong>re</strong> curved or<br />
slightly keeled in the apical ext<strong>re</strong>mities whe<strong>re</strong> an<br />
absence <strong>of</strong> the adaxial quadrate layer is f<strong>re</strong>quent.<br />
Tortella flavovi<strong>re</strong>ns shows g<strong>re</strong>at variability in<br />
the apex; on the same stem some apices may have<br />
costae subpercur<strong>re</strong>nt and the apices a<strong>re</strong> round in outline,<br />
or they may be flat to sharply tubulose and have<br />
percur<strong>re</strong>nt costae, or they can be narrowly acute with a<br />
strong mucro, but always at least some <strong>of</strong> the apices a<strong>re</strong><br />
naviculate and f<strong>re</strong>quently most a<strong>re</strong> cucullate. The<br />
species shows mo<strong>re</strong> variability in Europe, with cucullate<br />
apices in some populations to flat apices in others, but<br />
all with e<strong>re</strong>ct to incurved margins, lack <strong>of</strong> tomentum,<br />
larger leaf cells, and central strand p<strong>re</strong>sent.<br />
The proximal cell <strong>re</strong>gion in larger leaves is<br />
sharply distinguished from the distal laminal <strong>re</strong>gion by<br />
abruptly elongated smooth cells in contrast with the<br />
distal quadrate papillose cells. However, in many<br />
smaller leaves the transition is completely gradual in<br />
cell size and cell wall thickness such that the V-shaped<br />
<strong>re</strong>gion is defined mo<strong>re</strong> by the papillae than by the cell<br />
dimensions, and the proximal margin has a border <strong>of</strong><br />
mo<strong>re</strong> abruptly elongated proximal cells. This may<br />
account to some extent for European published <strong>re</strong>ports<br />
<strong>of</strong> the taxonomic proximity <strong>of</strong> this species with Tortella<br />
nitida, which has gradually transitional cells in all <strong>of</strong> its<br />
leaves with a sometimes poorly defined proximal<br />
marginal border <strong>of</strong> elongate cells. This situation is also<br />
rather characteristic <strong>of</strong> Tortella humilis and may align<br />
these th<strong>re</strong>e species, together with the leaf shape, stem<br />
central strand and undiffe<strong>re</strong>ntiated perichaetial leaves.<br />
The peristome <strong>of</strong> Tortella flavovi<strong>re</strong>ns is<br />
somewhat short, but not rudimentary: it is about half the<br />
size <strong>of</strong> that <strong>of</strong> T. humilis, for example, and is appa<strong>re</strong>ntly<br />
an example <strong>of</strong> <strong>re</strong>duction for the genus in North<br />
America. It is e<strong>re</strong>ct or somewhat inclined and<br />
<strong>re</strong>miniscent <strong>of</strong> Trichostomum peristomes, which a<strong>re</strong>
smooth, papillose or striolate and generally e<strong>re</strong>ct (some<br />
species in the world may be spiculose, Zander 1993).<br />
Tortella humilis overlaps in range that <strong>of</strong> T.<br />
flavovi<strong>re</strong>ns on the beaches <strong>of</strong> the southeastern United<br />
States, the only other species <strong>of</strong> the genus to do so, and<br />
characters that separate them a<strong>re</strong> critical. Most<br />
confusion in herbarium specimens a<strong>re</strong> between these<br />
two species. The su<strong>re</strong>st way to diffe<strong>re</strong>ntiate them is the<br />
nearly always p<strong>re</strong>sent autoicous perigonial bud <strong>of</strong> T.<br />
humilis which is absent in the dioicous T. flavovi<strong>re</strong>ns.<br />
Otherwise, the stem <strong>of</strong> T. flavovi<strong>re</strong>ns is elongate,<br />
usually two distinct annual whorls <strong>of</strong> leaves, with<br />
rhizoids few, coarse and confined to the base. Tortella<br />
humilis typically has a rosulate habit, with short,<br />
densely foliose, darker stems densely and finely<br />
tomentose up the stem. The former species ra<strong>re</strong>ly fruits<br />
and fruiting material is thus a strong candidate for<br />
Tortella humilis. When Tortella flavovi<strong>re</strong>ns does fruit,<br />
the peristome teeth a<strong>re</strong> e<strong>re</strong>ct or somewhat oblique, an<br />
unusual featu<strong>re</strong> for the genus, whe<strong>re</strong>as T. humilis is<br />
nearly always in a fruiting condition, is autoicous, male<br />
buds a<strong>re</strong> always conspicuous on dissection, and the<br />
peristome teeth a<strong>re</strong> long and twisted 2–3 times. Tortella<br />
flavovi<strong>re</strong>ns has larger leaf cells, 10–12(–14) µm wide,<br />
and narrowly incurved apical margins grading to<br />
cucullate apices that a<strong>re</strong> keeled. The cells <strong>of</strong> T. humilis<br />
a<strong>re</strong> 6–7(–9) µm wide, and it has broadly acute apices<br />
with plane or e<strong>re</strong>ct margins. If a doubtful T. flavovi<strong>re</strong>ns<br />
grows on anything but sand, it is probably T. humilis<br />
instead.<br />
In North America Tortella flavovi<strong>re</strong>ns may be<br />
separated from T. inclinata s.l. by distribution: T.<br />
flavovi<strong>re</strong>ns is a southern maritime species whe<strong>re</strong>as T.<br />
inclinata s.l. is northern (the G<strong>re</strong>at Lakes <strong>re</strong>gion to<br />
Alaska). Otherwise Tortella inclinata s.l. has no central<br />
strand, no quadrate, papillose cells on the adaxial<br />
surface <strong>of</strong> the costa, and has mo<strong>re</strong> tomentum on the<br />
stem. Its proximal V-shape <strong>of</strong> hyaline cells is distinct in<br />
all leaves, it has strongly diffe<strong>re</strong>ntiated perichaetial<br />
leaves when archegonia a<strong>re</strong> fertilized, and a long<br />
peristome twisted perhaps twice in <strong>re</strong>cently<br />
deoperculated capsules. It is due to these characters that<br />
T. inclinata is probably mo<strong>re</strong> aligned with T. tortuosa,<br />
and T. flavovi<strong>re</strong>ns with T. humilis.<br />
Tortella nitida, when it is confused with T.<br />
flavovi<strong>re</strong>ns in Europe, usually may be first distinguished<br />
by substrate. The latter species <strong>re</strong>qui<strong>re</strong>s coastal sand, if<br />
it is not an obligate halophyte. The former occurs on<br />
cliff faces, rocks and walls, appa<strong>re</strong>ntly not on sand or<br />
sandy soil. The leaves <strong>of</strong> typical T. nitida will not have<br />
sharply diffe<strong>re</strong>ntiated proximal cells in most <strong>of</strong> its<br />
leaves, and the proximal border <strong>of</strong> elongate hyaline cells<br />
will be confined to the margin <strong>of</strong> the leaf. Sections <strong>of</strong><br />
the leaf <strong>of</strong> T. nitida will display occasional bistratose<br />
pairs in the guide cell <strong>re</strong>gion; T. flavovi<strong>re</strong>ns will never<br />
have this. Note that the apices <strong>of</strong> T. nitida may have<br />
inflexed margins, but <strong>re</strong>semble mo<strong>re</strong> T. humilis than T.<br />
flavovi<strong>re</strong>ns. The leaf cell size <strong>of</strong> T. nitida is the same as<br />
T. humilis, around 7–10 µm, rather than the 10–12(–14)<br />
µm range <strong>of</strong> T. flavovi<strong>re</strong>ns.<br />
11<br />
If one accepts that the peristome illustrated<br />
he<strong>re</strong> for Tortella nitida is the true one, in contradiction<br />
to published <strong>re</strong>ports (see discussion <strong>of</strong> T. nitida below),<br />
then it and that <strong>of</strong> T. flavovi<strong>re</strong>ns a<strong>re</strong> nearly the same in<br />
character: shorter by about half that <strong>of</strong> Tortella tortuosa<br />
and other Tortella species with long-twisted peristomes,<br />
e<strong>re</strong>ct and densely spiculose, mo<strong>re</strong> like that <strong>of</strong> the genus<br />
Trichostomum as cur<strong>re</strong>ntly understood.<br />
Sterile Weissia species may be confused with<br />
T. flavovi<strong>re</strong>ns, being pale yellow with the same cell size,<br />
and appearing to have a cucullate apex with the<br />
marginal proximal cells somewhat extending up the<br />
leaf: these will, however, have no marginal extension on<br />
some leaves and the distal leaf margins will be tightly<br />
inrolled or incurved to a stronger deg<strong>re</strong>e than in any<br />
Tortella species; the substrate is f<strong>re</strong>quently<br />
inappropriate in these specimens, such as bark at the<br />
base <strong>of</strong> t<strong>re</strong>es or some other woody or humic substrate,<br />
likewise inland stations.<br />
Weissia jamaicensis (Mitt.) Grout is<br />
occasionally confused with Tortella flavovi<strong>re</strong>ns. Both<br />
have strong central strands and a lemon-g<strong>re</strong>en color,<br />
with hyaline cells running somewhat up the proximal<br />
margins. Weissia jamaicensis is distinguished by its<br />
long, linear-lanceolate leaves and much mo<strong>re</strong> sharply<br />
incurving margins running from proximal mid-leaf to<br />
the apex in every leaf. Tortella flavovi<strong>re</strong>ns is <strong>re</strong>stricted<br />
to coastal stations whe<strong>re</strong>as Weissia jamaicensis may be<br />
found inland.<br />
Trichostomum crispulum, with which Tortella<br />
flavovi<strong>re</strong>ns has occasionally been confused, has smaller<br />
leaf cells, a broader, chestnut-colo<strong>re</strong>d costa and has a Ushaped<br />
proximal diffe<strong>re</strong>ntiated a<strong>re</strong>a <strong>of</strong> cells in all leaves.<br />
As discussed above, Tortella flavovi<strong>re</strong>ns var.<br />
glariecola (Christens.) Crundw. & Nyholm is<br />
distinguished from the typical variety by having cells in<br />
the distal part <strong>of</strong> the leaf <strong>re</strong>gularly 10–14 µm wide. In a<br />
European specimen <strong>of</strong> this variety that was seen, the<br />
a<strong>re</strong>olation is indeed distinctive because most <strong>of</strong> the cells<br />
a<strong>re</strong> <strong>of</strong> these dimensions, and the cell walls appear to be<br />
thicker. Specimens labeled as this from North America,<br />
however, have smaller cells overall, characteristic <strong>of</strong> the<br />
typical variety, with only occasional cells <strong>re</strong>aching 14<br />
µm. Crundwell and Nyholm (1962) suggested that<br />
larger cell size in this species is cor<strong>re</strong>lated with northern<br />
location. Nothing identifiable as the var. glariecola was<br />
found in American populations <strong>of</strong> T. flavovi<strong>re</strong>ns var.<br />
flavovi<strong>re</strong>ns.<br />
Smith (1978) gave a <strong>re</strong>cord for Tortella<br />
flavovi<strong>re</strong>ns var. glariecola occurring in Canada, most<br />
likely based on the citation by Crundwell and Nyholm<br />
(1962) <strong>of</strong> a depauperate specimen <strong>of</strong> var. glariecola<br />
from Alberta collected by C. D. Bird 3624, identified by<br />
him as T. tortuosa. They state that "the occur<strong>re</strong>nce <strong>of</strong><br />
any variety <strong>of</strong> T. flavovi<strong>re</strong>ns in Alberta is exceedingly<br />
strange." These plants "with longly tapering acutely<br />
pointed leaves" may be one <strong>of</strong> the peculiar instances <strong>of</strong><br />
depauperate, large-celled T. tortuosa specimens (see<br />
discussion under that species). T. rigens, with leaf cell<br />
sizes to 14 µm, also may have long-pointed leaves, but
the absence <strong>of</strong> quadrate cells on the adaxial surface <strong>of</strong><br />
the costa is characteristic <strong>of</strong> that species. The substrate,<br />
at the base <strong>of</strong> a cottonwood t<strong>re</strong>e, is not typical <strong>of</strong> that<br />
species.<br />
One alternative is that the collection seen was<br />
Tortella alpicola. Crundwell had seen and annotated<br />
several specimens <strong>of</strong> that species from North America<br />
in North American herbaria, speculating that they had<br />
an affinity with Tortella rigens due to their leaf cells<br />
attaining 14 µm. Tortella alpicola has been <strong>re</strong>cently<br />
<strong>re</strong>ported from Alberta (Eckel 1997). I<strong>re</strong>land et al. (1987)<br />
in their checklist <strong>of</strong> the mosses <strong>of</strong> Canada conside<strong>re</strong>d<br />
the variety Tortella flavovi<strong>re</strong>ns var. gla<strong>re</strong>icola to be<br />
excluded from Canada.<br />
3. TORTELLA ALPICOLA Plate 3<br />
Tortella alpicola Dix., Ann. Bryol. 3: 54. 1930.<br />
Sarconeurum tortelloides S. W. G<strong>re</strong>ene, Sci.<br />
Rep. Brit. Antarct. Surv. 64: 38. 1970.<br />
Tortella tortelloides (S. W. G<strong>re</strong>ene) Robins. in<br />
Llano, Antarct. Terr. Biol., Antarct.<br />
Res. Ser. 20: 170. 1972.<br />
Tortella fragilis var. tortelloides (S. W.<br />
G<strong>re</strong>ene) Zand. & Hoe, Bryologist 82:<br />
84. 1979.<br />
Plants scatte<strong>re</strong>d or in s<strong>of</strong>t, loose or close tufts,<br />
light or dark and vivid or clear g<strong>re</strong>en above, pale buffbrown<br />
below with glistening white leaf bases, elongate,<br />
not rosulate. Stems thin, slender, 0.5–1(–1.5) cm,<br />
branches few to several, central strand p<strong>re</strong>sent and<br />
conspicuous, not tomentose except in perichaetiate<br />
plants. Stem leaves loosely foliose, densely so in<br />
perichaetiate plants, appearing s<strong>of</strong>t but actually rather<br />
rigid, fragile, closely to loosely agg<strong>re</strong>gated, uniform in<br />
size, apices in sterile plants (except the youngest)<br />
usually fallen, incurved-circinate and weakly contorted<br />
when dry, e<strong>re</strong>ct-sp<strong>re</strong>ading, occasionally patent when<br />
moist, gradually long-lanceolate, 1.5–2 mm; base<br />
undiffe<strong>re</strong>ntiated or somewhat broader than the limb,<br />
elliptical; margins <strong>of</strong> some leaves weakly undulate,<br />
constricted, lobed in scallop-shapes in several places<br />
distally, e<strong>re</strong>ct to incurved; apex narrowly acuminate,<br />
occasionally sharply contracted into a subula in the<br />
apical 1/3, this a papillose cylinder about the size <strong>of</strong> the<br />
costa, composed <strong>of</strong> a series <strong>of</strong> bar<strong>re</strong>l-shaped<br />
constrictions disarticulating in segments, intact subula<br />
and tip <strong>of</strong> propaguloid apex with an apiculus <strong>of</strong> several<br />
cells, this usually dentate and tipped by one or two,<br />
elongate, sharply pointed clear cells, in sterile plants<br />
leaf apices caducous along zones <strong>of</strong> weakness, youngest<br />
leaves at the stem tips composed enti<strong>re</strong>ly <strong>of</strong> a serially<br />
constricted, multistratose, awl-shaped propagulum,<br />
these usually absent in matu<strong>re</strong> leaves; costa shortexcur<strong>re</strong>nt,<br />
in leaves <strong>of</strong> fertile plants adaxial surface<br />
cove<strong>re</strong>d distally by an epidermis <strong>of</strong> quadrate, papillose<br />
laminal cells, back <strong>of</strong> the costa smooth throughout—in<br />
leaves <strong>of</strong> fragile sterile plants abaxial costa surface<br />
smooth only below apical subula, densely papillose on<br />
12<br />
both adaxial and abaxial surfaces in the distal<br />
subulate <strong>re</strong>gion, in cross section cells weakly<br />
diffe<strong>re</strong>ntiated and f<strong>re</strong>quently rather chaotic, adaxial<br />
epidermis always p<strong>re</strong>sent, rather thin-walled adaxial and<br />
abaxial subste<strong>re</strong>id layers p<strong>re</strong>sent, the adaxial ste<strong>re</strong>id<br />
cells <strong>of</strong>ten disappearing in the distal <strong>re</strong>gion <strong>of</strong> the leaf,<br />
guide cells in one row, <strong>of</strong>ten chlorophyllose; proximal<br />
laminal cells abruptly diffe<strong>re</strong>ntiated from distal cells,<br />
distinct in color, cell size, cell wall thickness and<br />
papillosity, pale white-hyaline and transpa<strong>re</strong>nt, shaped<br />
marginal angles <strong>of</strong> diffe<strong>re</strong>ntiated proximal cells steep;<br />
distal laminal cells <strong>re</strong>latively large, 10–14 µm wide,<br />
lamina unistratose but appa<strong>re</strong>ntly bistratose at junctu<strong>re</strong><br />
<strong>of</strong> lamina and costa, especially along the distal costa in<br />
propaguloid leaves <strong>of</strong> sterile plants; marginal cells<br />
undiffe<strong>re</strong>ntiated, papillose-c<strong>re</strong>nulate throughout.<br />
Asexual <strong>re</strong>production: modification for asexual<br />
<strong>re</strong>production in two modes, a general fragility <strong>of</strong> the leaf<br />
lamina as well as smaller, s<strong>of</strong>t, multistratose,<br />
propaguloid deciduous leaf apices articulated by <strong>re</strong>gular<br />
constrictions, falling early in units <strong>of</strong> approximately<br />
uniform length. Leaf apices generally absent due to the<br />
modified apices falling <strong>of</strong>f when the young leaves we<strong>re</strong><br />
formed, ra<strong>re</strong>ly <strong>re</strong>tained on matu<strong>re</strong> leaves. Sexual<br />
condition: appa<strong>re</strong>ntly dioicous. Perigonia not seen.<br />
Perichaetiate stems tomentose, perichaetia terminal on<br />
successive perichaetial innovations; outer perichaetial<br />
leaves diffe<strong>re</strong>ntiated, especially evident when dry,<br />
longer than the cauline leaves, long-lanceolate to linearlanceolate,<br />
fragile, tipped with long, rigid, subulate,<br />
smooth awns; these leaves rise above the contorted stem<br />
leaves when dry, proximal <strong>re</strong>gion broad, generally<br />
concolorous with the lamina, lamina quickly<br />
disappearing into the costa, or appearing to clothe the<br />
costa in a margin one or two cells wide for a distance<br />
befo<strong>re</strong> disappearing altogether, not propaguloid,<br />
unborde<strong>re</strong>d; inner perichaetial leaves long-triangular.<br />
Sporophytes unknown.<br />
Associated with shaded or exposed, wet or dry<br />
rocks, c<strong>re</strong>vices and ledges <strong>of</strong> granite, quartzite, schist,<br />
sandstone and calca<strong>re</strong>ous outcrops on cliffs and in<br />
canyons, in cracks in a limestone gully in a cavern on<br />
Ellesme<strong>re</strong> Island, but also in wet, mesic tundra (in the<br />
Yukon), and on a wet log (in Montana), in Quebec on<br />
dry limestone cliff face facing north; elevation 25–3300<br />
m; Alta., N.W.T., Que., Yukon; Alaska, Ariz., Colo.,<br />
Idaho, Mont., Nebr., Utah, Wyo.; South America in<br />
Colombia, Asia in India, Pacific Islands in Hawaii,<br />
Antarctica (Alexandra I.). I have verified all extra-<br />
American <strong>re</strong>cords he<strong>re</strong> cited.<br />
Herbaria examined: BUF, CANM, COLO,<br />
DUKE, MICH, MNA, MO, NY, UBC.<br />
The species in North America is associated<br />
with a western corridor <strong>of</strong> both montane and valley<br />
habitats, including the western G<strong>re</strong>at Plains, extending<br />
in an arc from Arizona to Ellesme<strong>re</strong> Island. The location<br />
<strong>of</strong> far eastern stations in the Gasp‚ Peninsula, Quebec<br />
(Mont Commis, St.-Donat de Rimouski, Lepage 3412<br />
MT; Compt‚ Gasp‚-Est, Cap-des Rosiers-Est, Forillon<br />
National Park, Brodo 18646 CANM) seems strikingly
anomalous, yet the disjunction is nearly identical with<br />
that <strong>of</strong> Molendoa sendtneriana (Bruch & Schimp. in<br />
B.S.G.) Limpr. This latter species is decidedly western<br />
cordilleran (Zander 1977) with an outlier in the province<br />
<strong>of</strong> Newfoundland (Belland and Brassard 1981 and Fife<br />
specimen 2380 BUF). Tortella alpicola is the only<br />
species <strong>of</strong> the genus known for Colombia (Churchill &<br />
Lina<strong>re</strong>s 1995).<br />
Tortella alpicola is the smallest <strong>of</strong> the North<br />
American Tortellae. The plants a<strong>re</strong> noted by their size,<br />
absence <strong>of</strong> tomentum on typical (sterile) stems, broken<br />
tips on most <strong>of</strong> the leaves, vividly shining white leaf<br />
bases on the stem in contrast with the deep or bright<br />
g<strong>re</strong>en <strong>of</strong> the limb, and large leaf cells (to 14 µm wide).<br />
In the two populations seen composed <strong>of</strong><br />
perichaetiate plants, the stems we<strong>re</strong> considerably mo<strong>re</strong><br />
densely foliose and the color somewhat mo<strong>re</strong> sordid, the<br />
ordinarily glistening leafbases yellowish and the<br />
tomentum very evident. These plants strongly <strong>re</strong>semble<br />
small stems <strong>of</strong> Tortella fragilis, due to the leaves with<br />
uniformly broken leaf tips surrounding a cluster <strong>of</strong> stiff<br />
and e<strong>re</strong>ct subulate leaves, which a<strong>re</strong>, in fact, the<br />
perichaetial leaves. The<strong>re</strong> never is a typical T. fragilis<br />
propagulum in the leaf apices <strong>of</strong> stem or perichaetial<br />
leaves.<br />
Small fertile plants <strong>of</strong> T. tortuosa and T.<br />
inclinata have a similar aspect; these also have stiff,<br />
awned perichaetial leaves distinct from the cauline<br />
leaves.<br />
The large leaf cells and p<strong>re</strong>sence <strong>of</strong> a distinct<br />
stem central strand in Tortella alpicola will diffe<strong>re</strong>ntiate<br />
ambiguous specimens from similarly small stems <strong>of</strong> T<br />
tortuosa and T. fragilis. The p<strong>re</strong>sence <strong>of</strong> such a featu<strong>re</strong><br />
aligns T. alpicola with species such as T. humilis, T.<br />
flavovi<strong>re</strong>ns in the United States, and T. nitida in Europe<br />
as well as certain species in the genus Trichostomum.<br />
This character may indicate that Tortella alpicola is<br />
ancestral to species in the genus with no stem central<br />
strand and similar leaf shape and perichaetial leaves. Its<br />
very broad distribution in the world may indicate that<br />
the species is older than at first suggested (Eckel 1991)<br />
and that it does not derive from T. fragilis or T. tortuosa<br />
(as per Zander & Hoe 1979; Eckel 1991).<br />
The consistently large leaf cell size (on average<br />
14 µm) is also distinctive, although note must be made<br />
<strong>of</strong> the smaller cells in one Arizona collection, which<br />
<strong>re</strong>tained all other characteristics, especially the peculiar<br />
propagula displayed at the leaf apex. Tortella rigens has<br />
leaf cells this large, but lacks quadrate, papillose adaxial<br />
epidermal cells on the costa, p<strong>re</strong>senting a generally<br />
smooth surface in an adaxial groove throughout the leaf<br />
length and has no stem central strand.<br />
These young leaves a<strong>re</strong> actually the emerging<br />
apices <strong>of</strong> the developing leaf. In one specimen from the<br />
Northwest Territories (Ellesme<strong>re</strong> Island, Brassard 4202<br />
CANM) the apical propagula had not fallen away and<br />
we<strong>re</strong> <strong>re</strong>tained until the leaf became fully matu<strong>re</strong>,<br />
producing a plant seemingly cove<strong>re</strong>d with worm-like<br />
apical appendages, the constrictions <strong>of</strong> these somewhat<br />
ir<strong>re</strong>gularly <strong>of</strong>fset from one another. The plants we<strong>re</strong><br />
13<br />
sterile and quite as foliose and several-branched as<br />
perichaetiate plants. The ra<strong>re</strong> occur<strong>re</strong>nce <strong>of</strong> leaves with<br />
intact propaguloid apices is likely due to their protected<br />
situation: "in cracks <strong>of</strong> limestone gully, deep inside<br />
cavern."<br />
The sense that the leaf is structurally mo<strong>re</strong><br />
prone to deterioration in Tortella alpicola parallels<br />
lamina characteristics <strong>of</strong> such species conspicuous in<br />
their erose leaves as Trichostomum tenuirost<strong>re</strong> and<br />
Tortella nitida, with ir<strong>re</strong>gularly scalloped, subdentate<br />
margins, the apex <strong>of</strong> the marginal sinus marking a point<br />
<strong>of</strong> weakness. Species without fragile leaves have<br />
generally straight and <strong>re</strong>gular margins.<br />
Tortella alpicola appa<strong>re</strong>ntly has dimorphic<br />
leaves: one kind in sterile plants, emphasizing fragility<br />
and asexual <strong>re</strong>production, and another when fertile and<br />
perichaetiate, in which the leaves a<strong>re</strong> mo<strong>re</strong> intact. When<br />
sterile, the distal and abaxial costal surface in fragile<br />
subulate leaf apices is densely papillose and hence has a<br />
dull appearance; thus T. alpicola is the only species in<br />
the genus in North America to <strong>re</strong>gularly have anything<br />
but a smooth, shining abaxial costal surface in the distal<br />
portion <strong>of</strong> the leaf. On the other hand some taxa in the<br />
genus he<strong>re</strong> under examination have a ra<strong>re</strong>ly exp<strong>re</strong>ssed<br />
tendency to form elongate leaf apices that a<strong>re</strong> tubulose<br />
or even cylindrical, with the suspicion <strong>of</strong> caducous<br />
tendencies in the leaf apex. These do develop abaxial<br />
papillae in this a<strong>re</strong>a and the condition is ra<strong>re</strong>ly seen in T.<br />
tortuosa var. fragilifolia. In Europe, T. nitidum var.<br />
irrigatum Winter possesses this characteristic<br />
(according to May 1986).<br />
The costal anatomy <strong>of</strong> leaves <strong>of</strong> Tortella<br />
alpicola shows two sets <strong>of</strong> characteristics, one for sterile<br />
plants and one for fertile (perichaetiate). In sterile<br />
plants, the costal layers (epidermis, ste<strong>re</strong>ids and guide<br />
cells) a<strong>re</strong> weakly diffe<strong>re</strong>ntiated and in many cases, not<br />
diffe<strong>re</strong>ntiated at all. It is perhaps this characteristic that<br />
led S. W. G<strong>re</strong>ene to originally place T. alpicola in the<br />
genus Sarconeurum Bryhn, in which, as Robinson<br />
(1972) noted, the costa "has less diffe<strong>re</strong>ntiation<br />
throughout and no diffe<strong>re</strong>ntiation in the cells adaxially."<br />
Sarconeurum also has a deciduous apical propagulum<br />
and a stem central strand. However, the proximal cells<br />
a<strong>re</strong> "completely diffe<strong>re</strong>nt and a<strong>re</strong> mo<strong>re</strong> like those <strong>of</strong><br />
Barbula" (Robinson 1972) and as Robinson suggested,<br />
other genera in the Pottiaceae have fleshy, deciduous<br />
leaf apices, Didymodon Hedw. being a good example.<br />
In sterile T. alpicola, the costa is undiffe<strong>re</strong>ntiated in the<br />
proximal part <strong>of</strong> the leaf whe<strong>re</strong> the laminae a<strong>re</strong> fully<br />
extended and unistratose. The laminae a<strong>re</strong> never fully<br />
bistratose but occasionally exhibit bistratose patches. In<br />
sterile plants, the epidermal and guide cell layers may<br />
be chlorophyllose and the<strong>re</strong> a<strong>re</strong> papillae on the abaxial<br />
surface <strong>of</strong> the costa. In Tortella fragilis, the costal cells<br />
become undiffe<strong>re</strong>ntiated in the non-laminate subula<br />
while the lamina just below the propagulum is<br />
bistratose.<br />
In perichaetiate plants the costa is not so<br />
amorphous. In sterile plants the abaxial ste<strong>re</strong>id band<br />
disappears along with the other layers. In perichaetiate
plants the abaxial and adaxial ste<strong>re</strong>id bands a<strong>re</strong> definite,<br />
with thick-walled cells. The adaxial ste<strong>re</strong>id layer,<br />
however, appears to quickly disappear in the distal<br />
<strong>re</strong>gion <strong>of</strong> the leaf, rather than the epidermal layer, the<br />
<strong>re</strong>verse <strong>of</strong> every Tortella species in North America<br />
(excepting many specimens <strong>of</strong> T. tortuosa var.<br />
fragilifolia), leaving a costal anatomy that <strong>re</strong>sembles<br />
that <strong>of</strong> the two Mexican endemic species <strong>of</strong><br />
St<strong>re</strong>ptocalypta, with either a rather undiffe<strong>re</strong>ntiated<br />
costa excepting the persistent abaxial ste<strong>re</strong>id band (S.<br />
santosii (Bartr.) Zand.) or one with in which the adaxial<br />
ste<strong>re</strong>id is absent and the adaxial epidermal cells a<strong>re</strong> not<br />
diffe<strong>re</strong>ntiated from the guide cells (S. tortelloides<br />
(Card.) Zand.). Other than this peculiarity <strong>of</strong> the costa,<br />
however, Tortella alpicola cannot be shown to have any<br />
other similarity with St<strong>re</strong>ptocalypta other than in<br />
characters sha<strong>re</strong>d by both genera, such as the high angle<br />
<strong>of</strong> the proximal cell <strong>re</strong>gion. Zander (1993) interp<strong>re</strong>ted<br />
these adaxial costal a<strong>re</strong>as as multistratose guide cells<br />
with an adaxial epidermis.<br />
The two other Tortella species in North<br />
America with stem central strands, Tortella humilis and<br />
T. flavovi<strong>re</strong>ns, have two well-diffe<strong>re</strong>ntiated, strong<br />
ste<strong>re</strong>id bands abaxial and adaxial to the guide cell layer.<br />
Both Tortella fragilis and T. tortuosa, when<br />
small, typically have rufous tomentum extending up the<br />
stem. Their leaf bases a<strong>re</strong> mo<strong>re</strong> yellow. In tiny plants <strong>of</strong><br />
T. fragilis, the margins a<strong>re</strong> <strong>re</strong>gular and sharply defined,<br />
almost stiff, rather than the c<strong>re</strong>nulate-papillose and<br />
scalloped or indented margins <strong>of</strong> T. alpicola. Both<br />
species have leaf cells smaller than 14 µm and neither<br />
has a stem central strand.<br />
The propaguloid modifications <strong>of</strong> the leaves<br />
a<strong>re</strong> diffe<strong>re</strong>nt in kind between Tortella fragilis and T.<br />
alpicola. The propagules <strong>of</strong> the former species fall as a<br />
single unit from leaves disposed all along the stem,<br />
whe<strong>re</strong>as those <strong>of</strong> the latter fall in numerous, fragile,<br />
bar<strong>re</strong>l-shaped caducous units <strong>of</strong> about equal length from<br />
the leaf apices.<br />
Tortella nitida (Lindb.) Broth. has been<br />
ascribed to the North American flora by Haring (1938)<br />
and Flowers (1973) among others (see also discussion<br />
below under T. tortuosa var. fragilifolia). These<br />
specimens have been suggested to be a variant <strong>of</strong> T.<br />
tortuosa by Crum and Anderson (1981), who also state<br />
that material cited as T. nitida by Haring was in fact<br />
either T. fragilis or T. tortuosa, and material from Utah,<br />
described by Flowers, was not seen by them. A few<br />
specimens labeled T. nitida from various herbaria in<br />
North America we<strong>re</strong> in fact one or the other <strong>of</strong> those<br />
two species. However, the specimens cited by Haring<br />
(1938) we<strong>re</strong> variously either T. tortuosa var. fragilifolia<br />
or T. alpicola, and <strong>of</strong> the two cited for Utah by Flowers<br />
(1973), the one available for study was T. alpicola.<br />
None <strong>of</strong> the th<strong>re</strong>e specimens cited by Haring was T.<br />
tortuosa or T. fragilis.<br />
Tortella nitida, a European species, has<br />
proximal cells gradually, not abruptly, diffe<strong>re</strong>ntiated<br />
from the laminal cells, a shining costa on the abaxial<br />
leaf surface with no distinctive subulate propaguloid<br />
14<br />
leaf apex, and leaf cells to 10 µm wide. Its leaves a<strong>re</strong><br />
usually broadly lanceolate to almost oblong-ligulate,<br />
whe<strong>re</strong>as those <strong>of</strong> all <strong>of</strong> the taxa just cited a<strong>re</strong> lanceolate<br />
to linear-lanceolate. Only T. alpicola and Trichostomum<br />
tenuirost<strong>re</strong> a<strong>re</strong> like it in its laminal fragility and stem<br />
central strand.<br />
North American material examined for the<br />
p<strong>re</strong>sent study, named Tortella nitida, is variously T.<br />
alpicola, T. fragilis, T. tortuosa and Trichostomum<br />
tenuirost<strong>re</strong>, with Tortella alpicola specimens<br />
p<strong>re</strong>dominating in the western United States <strong>of</strong> Utah and<br />
Colorado. Tortella alpicola differs from authentic<br />
European T. nitida immediately in the brightly distinct<br />
clear proximal cells set <strong>of</strong>f from the g<strong>re</strong>en laminal cells<br />
as well as the other characters mentioned. The<strong>re</strong> is a<br />
tiny specimen collected by R. S. Williams, "Columbia<br />
Falls, Montana, on wet log, Williams 329, Nov. 4 1895<br />
[NY]." It was identified by him as Trichostomum<br />
cylindricum (Brid.) C. Müll. (= Trichostomum<br />
tenuirost<strong>re</strong>), a species with forms that closely <strong>re</strong>semble<br />
Tortella alpicola. His analytical description <strong>of</strong> the plant<br />
fits the description given above for Tortella alpicola,<br />
but mo<strong>re</strong> particularly, his ca<strong>re</strong>ful and minute drawings<br />
<strong>of</strong> stem and leaf cross sections in the specimen packet<br />
show perfectly the undiffe<strong>re</strong>ntiated costal cells and the<br />
stem section with central strand <strong>of</strong> that species. This is<br />
the Montana specimen cited by Haring (1938) as T.<br />
nitida.<br />
Specimens <strong>of</strong> Tortella alpicola from North<br />
America have also been determined to be T. rigens N.<br />
Alberts. (Weber 1973) due to the wide leaf cells (ca. 14<br />
µm), but plants <strong>of</strong> that species have elongate, smooth<br />
cells on the adaxial surface <strong>of</strong> the costa throughout the<br />
leaf length, have no stem central strand, a<strong>re</strong> 1.5–3 cm<br />
high, tomentose, and lack diffe<strong>re</strong>ntiated apical<br />
propagula, although the leaf apices a<strong>re</strong> fragile (see also<br />
Nyholm 1989).<br />
The perichaetiate plants <strong>of</strong> Tortella alpicola<br />
we<strong>re</strong> found in a Nebraska collection from "rocky cliffs<br />
at edge <strong>of</strong> prairie, moss common, exposed on dry sand<br />
cove<strong>re</strong>d rock" on May 19 (Churchill 7302, COLO,<br />
MICH); also from Alberta on "soil, steep east-facing<br />
limestone outcrop, white spruce-aspen-birch woods,<br />
4500' [1364 m]" (Bird & Glenn 11046, CANM).<br />
Although the epithet "alpicola" indicates alpine stations,<br />
it is possible that the perichaetiate populations a<strong>re</strong><br />
associated with short-grass plains, and the sterile forms<br />
a<strong>re</strong> associated with montane stations such as in the<br />
Rocky Mountains, but not enough material is available<br />
to make generalities (see analogy with T. inclinata var.<br />
densa below).<br />
4. TORTELLA TORTUOSA Plates 4–5<br />
Tortella tortuosa (Hedw.) Limpr., Laubm. Deutschl. 1:<br />
604. 1888.<br />
Tortula tortuosa Hedw., Sp. Musc. 124. 1801.<br />
Barbula tortuosa (Hedw.) Web. & Mohr, Ind.<br />
Musci Pl. Crypt. 2. 1803.
Mollia tortuosa (Hedw.) Lindb., Musci Scand.<br />
21. 1879.<br />
Trichostomum tortuosum (Hedw.) Dix., Handb.<br />
Brit. Mosses ed. 1. 221. 1896.<br />
Plants in dense tufts, <strong>of</strong>ten forming deep and extensive<br />
sods, dull, g<strong>re</strong>en, yellow-g<strong>re</strong>en or yellow-brown above,<br />
brown below, becoming <strong>re</strong>ddish at higher latitudes and<br />
altitudes, elongate. Stems 1–6 cm high, leaves distantly<br />
disposed along the stem with the shining leaf bases<br />
usually appa<strong>re</strong>nt, branching tending to concentrate in<br />
the distal part, central strand nearly always absent,<br />
ra<strong>re</strong>ly p<strong>re</strong>sent, sclerodermis moderately developed, 2–<br />
3(–4) cells deep, cells <strong>of</strong> the central cylinder rather<br />
thick-walled, stems visibly tomentose with dense <strong>re</strong>dbrown<br />
radicles, ra<strong>re</strong>ly nearly eradiculose in very small<br />
stems. Stem leaves rather s<strong>of</strong>t, uniform in size, strongly<br />
crisped or contorted with spirally curled tips when dry,<br />
flexuose- to wide-sp<strong>re</strong>ading when moist, longlanceolate<br />
to linear-lanceolate, broadly to narrowly<br />
concave or nearly plane below to mo<strong>re</strong> or less keeled in<br />
the apical <strong>re</strong>gion, (2–)3–6.5(–7) mm long; base<br />
somewhat broader than limb, oblong; margins usually<br />
shortly and strongly undulate, evenly c<strong>re</strong>nulate by<br />
papillae, gradually subulate-acuminate, apex<br />
acumination confluent with the mucro, leaves at the<br />
ext<strong>re</strong>me stem apex surmounted by a stout, multicellular<br />
mucro, sometimes the mucro longer than the incipient<br />
lamina <strong>of</strong> young leaves at the stem apex; costa<br />
excur<strong>re</strong>nt as a long, smooth or denticulate mucro or<br />
short awn, usually composed <strong>of</strong> 5–10 rhomboidal cells,<br />
yellow or <strong>re</strong>ddish and shining, adaxial cells <strong>of</strong> the costa<br />
variable, costa above the leaf base to the distal median<br />
<strong>re</strong>gion cove<strong>re</strong>d by an epidermis <strong>of</strong> quadrate to short<strong>re</strong>ctangular<br />
(2:1) papillose cells, in the distal adaxial<br />
<strong>re</strong>gion variously with a narrow or broader central<br />
groove <strong>of</strong> exposed, smooth, elongate (8:1) ste<strong>re</strong>id cells,<br />
occasionally the groove conspicuous and extensive;<br />
15<br />
cross section lunate and broad, nearly flat on the<br />
adaxial surface in the median leaf <strong>re</strong>gion, rounder<br />
distally on the leaf, adaxial and abaxial ste<strong>re</strong>id bands<br />
p<strong>re</strong>sent, guide cells p<strong>re</strong>sent in one row; proximal<br />
laminal cells abruptly diffe<strong>re</strong>ntiated from distal cells in<br />
color, cell size, cell wall thickness and papillosity, with<br />
proximal cells hyaline, laxly thin-walled, marginal angle<br />
steep; distal laminal cells unistratose, quadrate, 7–10<br />
(12–13) µm wide, marginal cells undiffe<strong>re</strong>ntiated.<br />
Asexual <strong>re</strong>production: Modifications for asexual<br />
<strong>re</strong>production none except possibly through fragility <strong>of</strong><br />
the lamina in some populations, or weakness toward the<br />
apex. Sexual condition: dioicous, seldom fruiting.<br />
Perigoniate plants ra<strong>re</strong>; perigonia appa<strong>re</strong>ntly few per<br />
stem, inner perigonial bracts ovate and abruptly<br />
apiculate, scarcely longer than the antheridia, 0.5 mm<br />
long. Perichaetiate plants common; perichaetia<br />
numerous on the stem; perichaetial leaves diffe<strong>re</strong>ntiated<br />
even in unfertilized perichaetia, slender and e<strong>re</strong>ct at the<br />
base, long, 5–5.5 mm, somewhat sheathing, distal part,<br />
consisting mostly <strong>of</strong> costa, setaceous-subulate, e<strong>re</strong>ct, in<br />
fertile plants, stiff and slightly flexuose, distinct and<br />
conspicuous above the tightly crisped cauline leaves<br />
when dry, occasionally with a border <strong>of</strong> clear, elongate,<br />
thick-walled cells extending down from the apex in all<br />
or some leaves, occasionally the leaves without<br />
quadrate, papillose epidermal cells anywhe<strong>re</strong> on the<br />
adaxial surface <strong>of</strong> the costa in some or all leaves. Seta<br />
<strong>re</strong>d below, paler above, 0.9–2.7 (ra<strong>re</strong>ly 3.5) cm long.<br />
Capsule 1.5–3.3 mm long; annulus not vesiculose;<br />
operculum 1.5–2 mm long, nearly as long as the<br />
capsule; peristome teeth long and spirally wound 2 or 3<br />
times. Calyptra cucullate. Spo<strong>re</strong>s 10–12(–13) µm,<br />
papillae small and somewhat ir<strong>re</strong>gular in size and<br />
distribution, not punctate or fine.<br />
Spo<strong>re</strong>s matu<strong>re</strong> in late spring and summer (late<br />
June through August).<br />
KEY TO VARIETIES OF TORTELLA TORTUOSA<br />
1. Plants <strong>re</strong>d-g<strong>re</strong>en, appearing black below, densely foliose with a thick apical coma, leaf bases hidden; stems<br />
appearing atomentose but tomentum hidden in the bases <strong>of</strong> branch innovations; leaves not fragile, intact; leaves<br />
<strong>of</strong>ten strongly squarrose-<strong>re</strong>curved when wet, plane, not undulate; proximal laminal cells thick-walled and brownish,<br />
intergrading in shape and size with the distal cells, which a<strong>re</strong> <strong>of</strong>ten non-papillose in the a<strong>re</strong>a <strong>of</strong> merger; leaves<br />
broadly concave in section; costa at midleaf exposed adaxially by as much as four ste<strong>re</strong>id cells . . . . 4b. Tortella<br />
tortuosa var. arctica<br />
1. Plants g<strong>re</strong>en or yellow-g<strong>re</strong>en, appearing brown below, loosely foliose, some leaf bases exposed, only slightly<br />
comose at stem apex; stems conspicuously tomentose; leaves fragile or not, e<strong>re</strong>ct- to e<strong>re</strong>ct-sp<strong>re</strong>ading when wet;<br />
undulate or plane; proximal laminal cells thin-walled and hyaline, sharply diffe<strong>re</strong>ntiated in shape and size from the<br />
papillose distal cells, which a<strong>re</strong> papillose in the a<strong>re</strong>a <strong>of</strong> contact; leaves keeled in section, costa in apical <strong>re</strong>gion<br />
exposed adaxially by up to two ste<strong>re</strong>id cells in width or completely cove<strong>re</strong>d with an adaxial epidermis <strong>of</strong> quadrate<br />
papillose cells . . . . 2<br />
2. Leaves in tight, complex spirals when dry, appearing s<strong>of</strong>t or lax throughout the stem length, not fragile<br />
or erose, leaf tips nearly all p<strong>re</strong>sent; conspicuously undulate; leaf cross section without bistratose a<strong>re</strong>as<br />
beside the costa, the lamina uniformly unistratose, lamina intact, the costa always diffe<strong>re</strong>ntiated into guide<br />
cells, ste<strong>re</strong>ids and epidermal cells, adaxial ste<strong>re</strong>id layer never disappearing toward the apex, adaxial<br />
epidermal layer typically absent apically in a medial groove to two ste<strong>re</strong>id cells in width 4a. . . . . T.<br />
tortuosa var. tortuosa<br />
2. Leaves in loose, simple spirals or once circinate when dry, appearing firm or rigid, <strong>of</strong>ten fragile and<br />
erose, leaf tips <strong>of</strong>ten absent; inconspicuously undulate, especially when dry; leaf cross section with
16<br />
bistratose a<strong>re</strong>as beside the costa, the lamina ir<strong>re</strong>gularly bistratose in patches, lamina tatte<strong>re</strong>d, costa<br />
occasionally appearing undiffe<strong>re</strong>ntiated in apical <strong>re</strong>gion <strong>of</strong> the leaf, adaxial ste<strong>re</strong>id layer occasionally<br />
disappearing toward the apex, epidermal layer may be continuous throughout the leaf length . . . . 4c. T.<br />
tortuosa var. fragilifolia<br />
4a. TORTELLA TORTUOSA VAR. TORTUOSA<br />
Plate 4<br />
Leaves in complex spirals when dry, appearing s<strong>of</strong>t or<br />
lax, not fragile or erose, leaf apices nearly all p<strong>re</strong>sent;<br />
conspicuously undulate; distal laminal cells ra<strong>re</strong>ly<br />
attaining 12 µm, usually less, quadrate, papillose<br />
adaxial cells on the surface <strong>of</strong> the costa p<strong>re</strong>sent in the<br />
median leaf <strong>re</strong>gion or higher; leaf cross section without<br />
bistratose a<strong>re</strong>as beside the costa, the lamina uniformly<br />
unistratose, costa always diffe<strong>re</strong>ntiated into guide cells,<br />
ste<strong>re</strong>ids and epidermal cells, adaxial ste<strong>re</strong>id layer never<br />
disappearing toward the apex, adaxial epidermal layer<br />
typically absent to two ste<strong>re</strong>id cells wide near the stem<br />
apex.<br />
Common in calca<strong>re</strong>ous <strong>re</strong>gions in a diversity <strong>of</strong><br />
habitats such as exposed or fo<strong>re</strong>st-shaded rock c<strong>re</strong>vices,<br />
boulders, ledges <strong>of</strong> mountains or low, peaty soil and<br />
rotten wood, dry wooded hillsides or wet a<strong>re</strong>as such as<br />
Thuja swamps, banks <strong>of</strong> st<strong>re</strong>ams over humus, river<br />
margins, in northern <strong>re</strong>gions in wet tundra and<br />
solifluction lobes; elevation 100–3800 m; G<strong>re</strong>enland;<br />
Alta., B.C., N.B., Nfld., N.W.T., N.S., Ont., Que., Sask.,<br />
Yukon; Alaska, Calif., Colo., Idaho, Ill., Ind., Iowa,<br />
Maine, Mass., Mich., Minn., Mont., Nebr., Nev., N.H.,<br />
N.Mex., N.Y., N.C., Ohio, O<strong>re</strong>g., Penn., S.Dak., Tenn.,<br />
Tex., Utah, Vt., Va., Wash., Wisc., Wyo.; Mexico,<br />
Guatemala, Europe, Asia, n Africa. "Iceland; Svalbard,<br />
widely distributed in Europe; eastward across northern<br />
and Arctic Asiatic USSR; Central Asia; Japan (Stee<strong>re</strong><br />
1978).<br />
Herbaria examined: BUF, CANM, COLO,<br />
DUKE, FLAS, MICH, MO, NY, UBC.<br />
Tortella tortuosa in North America is a species<br />
<strong>of</strong> Temperate-North Temperate, Bo<strong>re</strong>al and Subarctic<br />
distribution and <strong>of</strong> higher elevations in lower latitudes.<br />
In northern <strong>re</strong>gions whe<strong>re</strong> their ranges overlap, T.<br />
tortuosa is mo<strong>re</strong> f<strong>re</strong>quently found mixed with T.<br />
fragilis. This is especially true in Canada.<br />
Numerous specimens growing on islands and<br />
the coastal mainland <strong>of</strong> British Columbia and southern<br />
Alaska in p<strong>re</strong>sumably hyperoceanic climatic situations<br />
show anomalies <strong>of</strong> substrate and certain morphological<br />
characteristics, such as deep sods <strong>of</strong> long-stemmed,<br />
densely comose stems, thick-walled proximal cells and<br />
an epiphytic habitat. These collections seem worthy <strong>of</strong><br />
further study, but their <strong>re</strong>lationship to Tortella tortuosa<br />
seems clear.<br />
In Europe the species is best developed and<br />
f<strong>re</strong>quently fruiting in montane fo<strong>re</strong>sts in the northern<br />
Alps (Braunmiller et al. 1971). These authors further<br />
<strong>re</strong>port that the plant is sterile near the borders <strong>of</strong> its<br />
range and it is nearly absent in the Lowlands. The<br />
species is discussed as a possible adventive in the<br />
Netherlands by Ruber (1973).<br />
Hyvönen (1991) has <strong>re</strong>ported a bipolar<br />
distribution <strong>of</strong> this species (s.l.) based on <strong>re</strong>ports for<br />
southern South America, such as by Seki (1974) who<br />
indicated its distribution the<strong>re</strong> as "West & South<br />
Patagonia and Tierra del Fuego." It was noted also by<br />
Matteri (1985, 1986). In the latter publication Matteri<br />
<strong>re</strong>ported that Tortella tortuosa possessed a bipolar<br />
distributional pattern that included "Bo<strong>re</strong>al-Patagonian<br />
taxa absent from Australasia.". One specimen <strong>of</strong> T.<br />
tortuosa seen from Patagonia was autoicous with<br />
stalked, flattened perigonial buds, and the suggestion<br />
was made that this specimen was Tortella knightii<br />
(Mitt.) Broth. instead, an Australasian species (Eckel<br />
1997). Re-examination <strong>of</strong> other specimens from<br />
southern South America in the light <strong>of</strong> this possibility<br />
may indicate that T. tortuosa is confined to the Northern<br />
Hemisphe<strong>re</strong>.<br />
The <strong>re</strong>port <strong>of</strong> Tortella tortuosa from Colombia<br />
by Churchill (1989) has been emended to<br />
Pseudosymblepharis schimperiana (Paris) Crum<br />
(Churchill & Lina<strong>re</strong>s 1995). These two species a<strong>re</strong><br />
notoriously difficult to distinguish whe<strong>re</strong> their ranges<br />
overlap. Delgadillo et al. (1995) in their bibliographic<br />
catalogue <strong>of</strong> neotropical mosses <strong>re</strong>port T. tortuosa from<br />
Colombia and Peru.<br />
The epithet <strong>re</strong>fers to the most striking<br />
characteristic <strong>of</strong> the species, its crisped leaves in spirals<br />
when dry which, together with the strongly undulate<br />
margins, is unlike other species in the genus or <strong>re</strong>lated<br />
genera. The long, multicellular, vit<strong>re</strong>ous awn confluent<br />
with the lamina is also distinctive.<br />
Only in very depauperate forms is Tortella<br />
tortuosa confused with T. fragilis, which has leaves<br />
mo<strong>re</strong> rigid, mo<strong>re</strong> or less e<strong>re</strong>ct, not or only slightly<br />
contorted when dry and <strong>re</strong>gularly fragile with<br />
propaguloid modifications in the leaf apex.<br />
Occasional specimens <strong>of</strong> Tortella tortuosa<br />
have large laminal cells, on average 12 µm wide and<br />
attaining 14 µm in individual cells. They seem to be<br />
distinguished by no other character (British Columbia,<br />
damp outcrop, Range Lake, 59°52N', 137°50'W, 1100<br />
m, W. B. Sch<strong>of</strong>ield 98194, UBC; New York State,<br />
Essex Co., 2500–2800 ft. (760–850 m), vertical rock,<br />
Redfearn 13444, UBC).<br />
Tortella tortuosa leaves a<strong>re</strong> never with<br />
incurved margins nor a<strong>re</strong> apically cucullate as in T.<br />
inclinata or in the younger leaves <strong>of</strong> T. rigens.<br />
Throughout the range <strong>of</strong> T. tortuosa occasional puzzling<br />
specimens may be found with cell sizes to 14 µm in the<br />
distal <strong>re</strong>gion <strong>of</strong> the leaves (Nebraska, Alberta, Arctic<br />
specimens). One specimen from Newfoundland<br />
(Waghorne, 25, NY) had plants with leaf cell sizes to 14<br />
µm in a collection that also contained rather typical T.<br />
tortuosa plants, as did specimens from Alberta (Crum &<br />
Sch<strong>of</strong>ield 5260, MICH; Bird & Lakusta 16219, MICH)
and Quebec (I<strong>re</strong>land 11186, MICH). These specimens<br />
may have the mucro <strong>re</strong>duced to a thin, weak, sharp<br />
apiculus with broader leaves, or the lamina <strong>re</strong>duced and<br />
the long mucro <strong>re</strong>tained; the cell walls may appear<br />
thicker than usual and the marginal papillae seem mo<strong>re</strong><br />
sharply salient, the c<strong>re</strong>nulations mo<strong>re</strong> prominent.<br />
Absence <strong>of</strong> adaxial epidermal cells on the costa<br />
throughout much <strong>of</strong> the distal portion <strong>of</strong> the leaf may<br />
suggest T. inclinata s.l., but epidermal cells may be<br />
found at least in the mid-proximal <strong>re</strong>gions <strong>of</strong> most<br />
leaves. R. Zander (pers. comm.) suggested these forms<br />
may be associated with the perichaetium and be<br />
modifications due to sex hormones. Examination <strong>of</strong><br />
these specimens showed them all to be non-fruiting<br />
perichaetiate plants. In some <strong>of</strong> the thinnest <strong>of</strong> the<br />
leaves the<strong>re</strong> may be a marginal border <strong>of</strong> epapillose<br />
cells somewhat indicative <strong>of</strong> T. fragilis leaves, and in<br />
cross section an occasional bistratose patch on the<br />
lamina—: these in T. tortuosa a<strong>re</strong> only in the<br />
perichaetial leaves or leaves associated with the<br />
perichaetium. An occasional perichaetiate population <strong>of</strong><br />
T. tortuosa looked strikingly like T. fragilis when the<br />
setaceous perichaetial leaves <strong>of</strong> T. tortuosa dominate the<br />
leaves at the stem apex—especially when they had<br />
diffe<strong>re</strong>ntiated border cells. F<strong>re</strong>quently several <strong>of</strong> these<br />
perichaetial leaves have clear (non-papillose) elongate,<br />
thick-walled cells along the margins toward the leaf<br />
apex, and sometimes these may be sharply serrulate by<br />
the projecting distal ends <strong>of</strong> the marginal cells. Cross<br />
sections <strong>of</strong> these leaves, however, <strong>re</strong>adily demonstrate<br />
that they a<strong>re</strong> not bistratose and that these a<strong>re</strong> not<br />
propaguloid leaves, they occur only at the stem apex<br />
whe<strong>re</strong> they envelop archegonia, while the stem leaves<br />
below them a<strong>re</strong> typical <strong>of</strong> the species. Occasional<br />
specimens determined as T. fragilis a<strong>re</strong> richly<br />
perichaetiate specimens <strong>of</strong> T. tortuosa with ext<strong>re</strong>mely<br />
long perichaetial leaves throughout the stem <strong>re</strong>sembling<br />
the subulate propagula at the leaf apices <strong>of</strong> the former<br />
species. The tips <strong>of</strong> these leaves, however, a<strong>re</strong> not<br />
swollen at the distal ends, but a<strong>re</strong> either uniform in<br />
length or diminish in circumfe<strong>re</strong>nce toward the leaf<br />
apex. Occasional perichaetiate populations <strong>of</strong> this type<br />
may have no quadrate, papillose cells anywhe<strong>re</strong> along<br />
the length <strong>of</strong> the costa on any leaves.<br />
Cell modification in perichaetiate leaves<br />
includes a tendency to thicker-walled cells, especially<br />
striking in the transitional a<strong>re</strong>a between the proximal<br />
and distal laminal cells whe<strong>re</strong> very thick walled cells<br />
extend far down toward the base adjacent to the costa.<br />
The transitional a<strong>re</strong>a between distal and proximal cells<br />
may be extensive. In some leaves on the same stem with<br />
mo<strong>re</strong> typical leaves, laminal cells in the proximal <strong>re</strong>gion<br />
complete with papillae may extend nearly to the leaf<br />
insertion, with the elongate, lax, smooth, hyaline cells<br />
<strong>re</strong>stricted to the leaf margins.<br />
Leaves <strong>of</strong> Tortella tortuosa with no quadrate<br />
papillose cells on the adaxial surface <strong>of</strong> the costa<br />
throughout their length a<strong>re</strong> always perichaetial leaves:<br />
sterile leaves just below them on the stem have the<br />
typical quadrate cells on the adaxial surface, or the stem<br />
17<br />
may bear only perichaetia in which case many or all<br />
<strong>of</strong> the leaves may have elongate smooth cells on the<br />
adaxial costa surface for the enti<strong>re</strong> leaf length.<br />
Fertility <strong>of</strong> Tortella tortuosa does not appear to<br />
be enhanced by wet conditions; fruiting and fertile<br />
plants a<strong>re</strong> found on dry habitats, such as on rock and<br />
cliff surfaces, as well as wet substrates, such as soil in<br />
bogs.<br />
Most published illustrations <strong>of</strong> the costa <strong>of</strong><br />
Tortella tortuosa a<strong>re</strong> taken from sections in the middle<br />
<strong>re</strong>gion <strong>of</strong> the leaf. The costa in fact is very <strong>re</strong>duced in<br />
size toward the leaf tip and the adaxial epidermis is<br />
usually absent the<strong>re</strong> by a width <strong>of</strong> two cells. Short,<br />
depauperate plants <strong>of</strong> this species with cor<strong>re</strong>spondingly<br />
<strong>re</strong>duced costae in their leaves may then show anomalous<br />
cross-sections much <strong>re</strong>sembling that <strong>of</strong> T. inclinata, i.e.<br />
keeled, with small and nearly circular costae without an<br />
adaxial epidermal layer.<br />
The distinctively keeled leaf cross-section <strong>of</strong> T.<br />
tortuosa is especially evident in the distal portion <strong>of</strong> the<br />
leaf. Occasionally in the median leaf <strong>re</strong>gion it is so<br />
broadly keeled that the leaf appears canaliculate.<br />
Occasionally, the leaf apices may be longsubulate<br />
and suggest T. fragilis, but the deciduous<br />
apices <strong>of</strong> that species a<strong>re</strong> usually obtusely thickened at<br />
the narrowed end. The narrow tips <strong>of</strong> T. tortuosa leaves<br />
narrow gradually to their glistening points, whe<strong>re</strong>as the<br />
leaves <strong>of</strong> T. fragilis a<strong>re</strong> mo<strong>re</strong> abruptly narrowed into the<br />
base <strong>of</strong> a subulate leaf tip. The mucro <strong>of</strong> T. tortuosa is<br />
longer, usually to 10 cells, whe<strong>re</strong>as that <strong>of</strong> T. fragilis is<br />
shorter, with to 5 or 6 cells or less.<br />
Small plants to 1 cm may be confused with T.<br />
alpicola, but the characters <strong>of</strong> stout mucro in subulate<br />
leaves, corksc<strong>re</strong>w twisting apices when dry, and<br />
undulate leaf margins in addition to the intact, nonpropaguloid<br />
leaf apices a<strong>re</strong> diagnostic <strong>of</strong> T. tortuosa as<br />
is the absence <strong>of</strong> a stem central strand and smaller<br />
laminal cells.<br />
Occasionally Tortella tortuosa has shorter,<br />
broad leaves with a <strong>re</strong>duced mucro, <strong>re</strong>sembling T.<br />
humilis. If the<strong>re</strong> a<strong>re</strong> no autoicous buds, then the<br />
p<strong>re</strong>sence <strong>of</strong> a stem central strand will confirm these as<br />
T. humilis. If the<strong>re</strong> a<strong>re</strong> no quadrate papillose cells on the<br />
adaxial surface <strong>of</strong> the costa on non perichaetiate (sterile)<br />
leaves, <strong>re</strong>fe<strong>re</strong>nce might be made to T. rigens and both<br />
varieties <strong>of</strong> T. inclinata.<br />
Tortella tortuosa exceptionally has a distinct<br />
central strand but this trait is generally absent. Stem<br />
sections <strong>of</strong>ten a<strong>re</strong> large, to 13 cells across the stem<br />
diameter, or mo<strong>re</strong>. The cell wall thickness gradually<br />
diminishes toward the center and what can be<br />
interp<strong>re</strong>ted as a central strand seems to be only the very<br />
thinnest walled cells at the center (usually two). When<br />
T. tortuosa has a definite central strand, the strand is<br />
like that <strong>of</strong> T. humilis or T. flavovi<strong>re</strong>ns whe<strong>re</strong> it is mo<strong>re</strong><br />
clearly distinguished by numerous cells smaller and<br />
with much thinner walls in contrast to the surrounding<br />
cells.<br />
Long-leaved Bryoerythrophyllum<br />
<strong>re</strong>curvirostrum (Hedw.) Chen can <strong>re</strong>semble T. tortuosa
macroscopically in its spiral, twisting leaf apices and<br />
glistening leaf bases due to inflated or lax, clear cells,<br />
but it never has the long, needle-like mucro and the<br />
margins a<strong>re</strong> strongly <strong>re</strong>curved, with the costa dull on the<br />
back. The<strong>re</strong> a<strong>re</strong> usually one or mo<strong>re</strong> coarse, ir<strong>re</strong>gular<br />
teeth associated with the short mucro or leaf apex.<br />
Trichostomum tenuirost<strong>re</strong>, with leaves also<br />
spirally twisted when dry, has hyaline proximal cells<br />
that extend indistinctly only a short way up the margin<br />
by a few cells in width, and the stem is not radiculose.<br />
In fruiting specimens, Tortella tortuosa will have long,<br />
spiraled peristome teeth. The teeth <strong>of</strong> Trichostomum a<strong>re</strong><br />
e<strong>re</strong>ct or slightly inclined and <strong>of</strong>ten rudimentary.<br />
Trichostomum tenuirost<strong>re</strong> usually has a large and<br />
distinct stem central strand, and the apex <strong>of</strong> the leaf<br />
<strong>of</strong>ten has low and distant teeth.<br />
The traditional t<strong>re</strong>atment <strong>of</strong> Tortella tortuosa<br />
in North America is <strong>re</strong>markable for its lack <strong>of</strong> problems<br />
in taxonomy. It leaves one unp<strong>re</strong>pa<strong>re</strong>d for the<br />
p<strong>re</strong>sentation <strong>of</strong> the species in the European literatu<strong>re</strong>. In<br />
Europe, a continent <strong>of</strong> physiographically complex<br />
micro<strong>re</strong>gions, the variation is either divided into several<br />
species or is conside<strong>re</strong>d to be a single species <strong>of</strong> g<strong>re</strong>at<br />
morphological variability united by a welter <strong>of</strong><br />
intergrading forms. Podpera's list (1954) <strong>of</strong> subspecific<br />
taxa shows five forms for the var. tortuosa and 22<br />
additional infraspecific taxa for a total <strong>of</strong> 27,<br />
demonstrating that the species is "oecomorphis dives"<br />
indeed.<br />
But how is it that North American Tortella<br />
tortuosa has been <strong>re</strong>ported as so uniform in its<br />
characteristics throughout the continent, and can this<br />
fact contribute to <strong>re</strong>solving some European problems by<br />
assuring systematists that some <strong>of</strong> the European<br />
infraspecific taxa a<strong>re</strong>, in fact, species? For example,<br />
the<strong>re</strong> is the issue <strong>of</strong> the central strand and its utility in<br />
giving specific rank to such taxa as Tortella<br />
bambergeri, T. brotheri (Broth.) Broth., and T.<br />
fleischeri (Bauer) Amann, all conside<strong>re</strong>d by various<br />
authors as varieties, forms, subspecies or synonyms <strong>of</strong><br />
T. tortuosa, yet all th<strong>re</strong>e have a distinct stem central<br />
strand.<br />
Meylan (1921) wrote that Tortella fleischeri<br />
and T. bambergeri in the F<strong>re</strong>nch Jura Mountains "a<strong>re</strong><br />
probably only forms or races <strong>of</strong> the polymorphic T.<br />
tortuosa. While studying the constancy <strong>of</strong> their principal<br />
diffe<strong>re</strong>ntiating character, which is the p<strong>re</strong>sence <strong>of</strong> the<br />
central strand, I can say in my opinion, this character<br />
has little value for this group. Typical T. tortuosa also<br />
sometimes p<strong>re</strong>sents a stem in which the central strand is<br />
completely absent, sometimes, on the contrary, a central<br />
strand with various deg<strong>re</strong>es <strong>of</strong> development. I have<br />
seen, for example, specimens well fruiting and<br />
<strong>re</strong>p<strong>re</strong>senting the typical species to include a large,<br />
distinct central strand. Limpricht and other authors,<br />
mainly Germans, have accorded a very g<strong>re</strong>at importance<br />
to the p<strong>re</strong>sence or absence <strong>of</strong> a central strand, mainly in<br />
various groups."<br />
In my experience with North American species<br />
<strong>of</strong> Tortella, the central strands, when they occur, have<br />
18<br />
little "various deg<strong>re</strong>es <strong>of</strong> development." Cells <strong>of</strong> the<br />
central cylinder in species characterized as having no<br />
central strand may get thinner-walled in the center <strong>of</strong><br />
the stem, but the definition <strong>of</strong> a central strand used he<strong>re</strong><br />
is a group <strong>of</strong> cells (mo<strong>re</strong> than two) in the stem center<br />
that a<strong>re</strong> abruptly smaller than the surrounding cells and<br />
have thinner walls.<br />
Throughout the range <strong>of</strong> Tortella tortuosa and<br />
its varieties arctica and fragilifolia, the occur<strong>re</strong>nce <strong>of</strong> a<br />
definite stem central strand was only found in a<br />
specimen from South Dakota in an otherwise typical<br />
plant, and another in Montana, one from Michigan<br />
(Emmet Co. on shady soil, Cecil Bay, 4 miles W <strong>of</strong><br />
Mackinaw City, R.R. I<strong>re</strong>land 4379, UBC); also in var.<br />
fragilifolia: Vermont, Haring 1939, NY, CANM (see<br />
discussion below).<br />
Sections we<strong>re</strong> also made at the bases <strong>of</strong> the<br />
longest stems examined (to 6 cm) to see whether a<br />
central strand may be exp<strong>re</strong>ssed in the initial stages <strong>of</strong><br />
growth, and lost later, or lost in branches, but all such<br />
specimens proved to lack a central strand anywhe<strong>re</strong><br />
throughout the stem length.<br />
The t<strong>re</strong>atment <strong>of</strong> Tortella tortuosa in Mexico<br />
(Zander 1994d), whe<strong>re</strong> a central strand is <strong>re</strong>ported for<br />
the species, is somewhat problematical due to the<br />
confusion <strong>of</strong> several specimens <strong>of</strong> Pseudosymblepharis<br />
schimperiana, which does have a central strand, with<br />
specimens used in p<strong>re</strong>paration for that description <strong>of</strong> T.<br />
tortuosa. In fact, the illustration for the latter species is<br />
probably that <strong>of</strong> Pseudosymblepharis, and not T.<br />
tortuosa.<br />
Ascribing too much "polymorphism" to a<br />
single species, Tortella tortuosa s.l., in Europe may<br />
disguise the floristic conclusion that Europe is an<br />
important center <strong>of</strong> diversity in the genus Tortella in the<br />
North Temperate Zone.<br />
4b. TORTELLA TORTUOSA VAR. ARCTICA Plate 5<br />
Tortella tortuosa var. arctica (Arn.) Broth. in Fedch.,<br />
Fl. As. Ros. 13: 160. 1918.<br />
Mollia tortuosa var. arctica Arn., Ark. f. Bot.<br />
13(2): 51. 1913.<br />
Tortella arctica (Arn.) Crundw. & Nyh., Trans.<br />
Brit. Bryol. Soc. 4: 187. 1963.<br />
Plants <strong>re</strong>d-g<strong>re</strong>en or yellow-g<strong>re</strong>en with a coppery sheen<br />
above to black below, in coarse, dense, stiff tufts or<br />
deep sods, elongate. Stems 0.8–7 cm high, leaves<br />
densely disposed on stem or in dense annual whorls<br />
distinctly separated by less foliose <strong>re</strong>gions, terminating<br />
in a thick multi-branched comal tuft, leaf bases hidden<br />
in foliose <strong>re</strong>gions, exposed in elongated ones, branch<br />
innovations disposed throughout the stem, central strand<br />
absent or occasionally p<strong>re</strong>sent, sclerodermis robust, 4–<br />
5(–6) cells thick, cells <strong>of</strong> central cylinder <strong>re</strong>latively<br />
thick-walled, tomentum absent or occasional, especially<br />
at the bases <strong>of</strong> innovations, or inconspicuous and hidden<br />
in the leaf axils. Stem leaves coarse, uniform in size<br />
along the stem, somewhat larger at the stem apex, 2.3–6
mm long, rigid, not fragile, when dry e<strong>re</strong>ct, becoming<br />
crisped at the leaf tips, when wet e<strong>re</strong>ct-sp<strong>re</strong>ading,<br />
occasionally squarrose-<strong>re</strong>curved, narrowly longlanceolate,<br />
quickly narrowing above an enlarged<br />
proximal <strong>re</strong>gion, forming a variably distinct and<br />
stiffened limb, gradually tapering toward and confluent<br />
with the apex, canaliculate to tubulose, never keeled, 4–<br />
5(–6) mm long; base oval to <strong>re</strong>ctangular-oblong,<br />
generally broader than the limb; margins e<strong>re</strong>ct and<br />
somewhat incurved, not to somewhat undulate, evenly<br />
c<strong>re</strong>nulate by papillae or smooth, gradually subulateacuminate,<br />
apex: acumination narrowly confluent with<br />
the mucro; costa excur<strong>re</strong>nt as a long, smooth or<br />
denticulate mucro or short awn, usually composed <strong>of</strong><br />
mo<strong>re</strong> than five rhomboidal cells, concolorous with the<br />
lamina, adaxial cells <strong>of</strong> the costa variable, costa in the<br />
median <strong>re</strong>gion usually cove<strong>re</strong>d medially by quadrate to<br />
short-<strong>re</strong>ctangular (2:1) papillose cells (epapillose if the<br />
lamina has no papillae), and in the distal adaxial <strong>re</strong>gion<br />
with a narrow central groove <strong>of</strong> exposed, smooth,<br />
elongate (8:1) ste<strong>re</strong>id cells; cross section lunate and<br />
broad, nearly flat on the adaxial surface in the median<br />
leaf <strong>re</strong>gion, adaxial epidermis p<strong>re</strong>sent and usually<br />
continuous in median leaf <strong>re</strong>gion, absent by about 4<br />
cells b<strong>re</strong>adth in the distal <strong>re</strong>gion, adaxial and abaxial<br />
ste<strong>re</strong>ids p<strong>re</strong>sent, guide cells p<strong>re</strong>sent in one row;<br />
proximal laminal cells <strong>of</strong>ten gradually diffe<strong>re</strong>ntiated<br />
from distal cells, displaying a zone <strong>of</strong> cells intermediate<br />
in color, cell size and papillosity, with an intermediate<br />
zone <strong>of</strong> thick-walled porose proximal cells, yellow,<br />
elongate, firm, seldom laxly thin-walled except at the<br />
insertion, smooth; marginal angle steep and defined by<br />
cell length and smoothness, with a line <strong>of</strong> longer cells<br />
extending a short way up the lamina; distal laminal<br />
cells unistratose, rounded-quadrate or hexagonal to<br />
rounded (with inc<strong>re</strong>ase in wall thickness), (7–)10–12(–<br />
13) µm wide, incrassate, strongly papillose or the<br />
papillae appa<strong>re</strong>ntly undeveloped at the expense <strong>of</strong><br />
strongly thickened cell walls, the papillae when p<strong>re</strong>sent<br />
small to massive and obscuring the cell lumen; marginal<br />
cells undiffe<strong>re</strong>ntiated. Asexual <strong>re</strong>production:<br />
modifications for asexual <strong>re</strong>production none. Sexual<br />
condition: dioicous. Perigonia not seen. Perichaetia<br />
terminal, inner perichaetial leaves long-linear, laxly<br />
subulate, the costa sometimes extending beyond the<br />
<strong>re</strong>duced lamina into a naked subula, perichaetial leaves<br />
longer than the stem leaves, to 10 mm in length, distal<br />
lamina confluent with a long or short subula.<br />
Sporophyte: fruiting plants not seen.<br />
Usually associated with mo<strong>re</strong> moistu<strong>re</strong> than the<br />
typical variety: dep<strong>re</strong>ssions in mesic to wet tundra, soil<br />
over limestone and sandstone above timberline in Arctic<br />
Canada and mountain peaks in the Rocky Mountains,<br />
below snowfields, in hillside and mountain seepage and<br />
seepage channels, bordering st<strong>re</strong>ams and ponds, wet<br />
rock surfaces, fens, wet frost boils, f<strong>re</strong>quently on ridges<br />
in the wetter a<strong>re</strong>as; in Ca<strong>re</strong>x-Eriophorum meadows,<br />
Dryas communities, Cassiope heaths; wet sandy<br />
Eriophorum triste meadow (N G<strong>re</strong>enland), in the Arctic<br />
19<br />
from sea level to 800 m, in the Rocky Mountains to<br />
3600 m.<br />
G<strong>re</strong>enland, Lab., N.W.T., B.C., Nfld., Yukon;<br />
Alaska, Colo., Maine, Siberia; in North America in the<br />
Arctic "with a disjunct distribution southward in the<br />
western mountains to northern British Columbia and<br />
Colorado. Distributed across Arctic Asiatic USSR and<br />
in northwest Yunnan" (Stee<strong>re</strong> 1978).<br />
Herbaria examined: BUF, CANM, COLO,<br />
DUKE, MICH, MO, NY, UBC.<br />
Other than high altitude <strong>re</strong>ports from<br />
mountains in the north temperate zone, this variety is<br />
best and most abundantly p<strong>re</strong>sent in the wet lowlands <strong>of</strong><br />
the coasts <strong>of</strong> seas, gulfs and bays <strong>of</strong> the Arctic Ocean.<br />
The variety is easily distinguished when the<br />
leaf cells a<strong>re</strong> ext<strong>re</strong>mely thick-walled and obscu<strong>re</strong>d by<br />
massive papillae, and the proximal cells grade so<br />
gradually into the distal laminal cells as to be<br />
indistinguishable except for their length. However,<br />
intermediates in anatomical characters a<strong>re</strong> abundant in<br />
mo<strong>re</strong> temperate situations in a zone between north<br />
bo<strong>re</strong>al <strong>re</strong>gions and the Arctic (ext<strong>re</strong>me north).<br />
Intermediate specimens a<strong>re</strong> also found at higher<br />
elevations in the south Bo<strong>re</strong>al zone and in wet<br />
continental (coastal) margins in the ext<strong>re</strong>me northern<br />
Arctic and G<strong>re</strong>enland.<br />
The most distinctive <strong>re</strong>p<strong>re</strong>sentative specimens<br />
a<strong>re</strong> a blackened brick-<strong>re</strong>d, with very long stems, and so<br />
densely foliose with rigid leaves as to appear to felt the<br />
substrate on which they grow with woolly mats.<br />
However, in sites that have mo<strong>re</strong> temperate conditions,<br />
especially at the southern limit <strong>of</strong> its range, the species<br />
varies such that the stems may be less foliose, hence<br />
less dense except in innovating whorls and at the apex,<br />
the dry leaves become mo<strong>re</strong> contorted at the stem apex,<br />
the <strong>re</strong>d color subsides toward the yellow-g<strong>re</strong>en <strong>of</strong> T.<br />
tortuosa, the sclerodermis <strong>re</strong>cedes to <strong>re</strong>semble that <strong>of</strong><br />
the typical variety and the distal laminal cells have<br />
thinner walls, tiny papillae and a<strong>re</strong> strikingly set <strong>of</strong>f<br />
from the proximal cells which a<strong>re</strong> thin and lax, clear and<br />
f<strong>re</strong>e <strong>of</strong> papillae. Such plants then have mo<strong>re</strong> tortuous<br />
leaves when dry.<br />
In such specimens, one must <strong>re</strong>ly for<br />
identification on the <strong>re</strong>latively denser habit, at least at<br />
the stem apex, the leaf shape, with its broader leaf base<br />
and mo<strong>re</strong> abruptly contracted, mo<strong>re</strong> rigid distal lamina,<br />
the tubular or canaliculate leaf cross section (not keeled)<br />
and the tomentum hidden in the bases <strong>of</strong> the leaves<br />
(rather than exposed). Note that the proximal cells <strong>of</strong> the<br />
dry leaves a<strong>re</strong> generally not distinct macroscopically on<br />
the stem by their coloring (being concolorous with the<br />
distal laminal cells), whe<strong>re</strong>as in Tortella tortuosa var.<br />
tortuosa the glistening, <strong>re</strong>latively colorless (pale yellow)<br />
leaf bases a<strong>re</strong> usually prominent. Proximal cells <strong>of</strong> var.<br />
arctica a<strong>re</strong> usually the same color as the lamina only<br />
paler due to their transpa<strong>re</strong>ncy. The<strong>re</strong> is a zone <strong>of</strong><br />
smooth proximal cells that a<strong>re</strong> as thick-walled as the<br />
distal laminal ones, whe<strong>re</strong>as in var. tortuosa the<strong>re</strong> is<br />
usually an abrupt diffe<strong>re</strong>nce between the chlorophyllose<br />
distal laminal cells and the hyaline proximal cells, and
an abrupt change between the thicker walled papillose<br />
distal laminal cells and the lax, thin-walled smooth<br />
proximal ones.<br />
Crundwell and Nyholm (1963) give an<br />
excellent account <strong>of</strong> this taxon, t<strong>re</strong>ating it at the species<br />
level. Although Tortella tortuosa var. arctica may<br />
<strong>re</strong>place var. tortuosa in the high Arctic, the variety does<br />
range to the south into Maine and Colorado. In latitudes<br />
whe<strong>re</strong> the two varieties overlap, their diffe<strong>re</strong>ntiation<br />
becomes highly problematical. Arctic and high alpine<br />
material <strong>of</strong> var. arctica easily show their special<br />
characteristics. Unfortunately, as Crundwell and<br />
Nyholm suggest, the<strong>re</strong> a<strong>re</strong> many specimens in mo<strong>re</strong><br />
southern latitudes that exhibit clearly and sharply<br />
diffe<strong>re</strong>ntiated proximal cells, mo<strong>re</strong> lax and strongly<br />
undulate leaves, mo<strong>re</strong> g<strong>re</strong>enish coloration to make it<br />
very difficult to diffe<strong>re</strong>ntiate the two taxa with<br />
confidence.<br />
The further away from tundra conditions, the<br />
less highly colo<strong>re</strong>d do specimens <strong>of</strong> var. arctica become.<br />
This <strong>re</strong>d coloration was discussed by Stee<strong>re</strong> (1976: 54–<br />
55) for individual variation, but some points might<br />
apply to latitudinal and altitudinal adaptations <strong>of</strong> taxa at<br />
the varietal level: "To sum up, tundra bryophytes, with<br />
very few exceptions, a<strong>re</strong> wholly tolerant <strong>of</strong> insolation,<br />
and many <strong>of</strong> them develop a 'sun-<strong>re</strong>d' pigmentation as<br />
the <strong>re</strong>sult <strong>of</strong> full insolation, as Mesoptychia sahlbergii<br />
and Climacium arcticum, which a<strong>re</strong> <strong>of</strong>ten associated and<br />
yet which may lack the <strong>re</strong>d pigment when protected<br />
from the di<strong>re</strong>ct sun, as on steep north-facing<br />
mountainsides, whe<strong>re</strong> they grow in the shade <strong>of</strong> slump<br />
terraces. In fact, most tundra bryophytes tend to be<br />
considerably mo<strong>re</strong> pigmented in full sun than when<br />
growing in shade."<br />
The mo<strong>re</strong> highly colo<strong>re</strong>d <strong>re</strong>ddish characteristics<br />
<strong>of</strong> most populations <strong>of</strong> Tortella inclinata var. densa may<br />
also be a <strong>re</strong>sponse to insolation.<br />
Crundwell and Nyholm (1963) also discuss in<br />
detail the ecology <strong>of</strong> var. arctica, emphasizing the<br />
association <strong>of</strong> this species with wet soil in seepage or<br />
poor drainage, a<strong>re</strong>as that may be dry late in the season.<br />
The difficulty <strong>of</strong> verifying these ecological generalities<br />
is the inadequacy <strong>of</strong> the data on labels. Many mention<br />
no substrate at all and an equal number mention basalt,<br />
granite, limestone outcrops, ridges and cliffs, a<strong>re</strong>as one<br />
would assume we<strong>re</strong> dry, except if the collector<br />
happened to mention seepage.<br />
The sclerodermis <strong>of</strong> var. arctica can be a thick<br />
rind around the central cylinder. For the Russian moss<br />
flora, Savicz-Ljubitzkaja and Smirnova (1970), who<br />
likewise conside<strong>re</strong>d var. arctica a variety <strong>of</strong> Tortella<br />
tortuosa, illustrated the small stem central strand that is<br />
inf<strong>re</strong>quently p<strong>re</strong>sent in the American Arctic (it is as ra<strong>re</strong><br />
as in var. tortuosa.) They indicated in their drawings<br />
that both varieties can have the thick sclerodermis.<br />
Fruiting plants we<strong>re</strong> not seen, and fertile<br />
specimens <strong>of</strong> var. arctica we<strong>re</strong> not <strong>of</strong>ten encounte<strong>re</strong>d:<br />
th<strong>re</strong>e perichaetiate plants we<strong>re</strong> seen, one from Maine,<br />
another from Melville Island and one from the Yukon.<br />
20<br />
Intermediate populations occur in O<strong>re</strong>gon<br />
(Saddle Mountain, Clatsop Co., Sch<strong>of</strong>ield & Christy<br />
81863, UBC). These a<strong>re</strong> dark <strong>re</strong>d plants with thickened<br />
cell walls with the proximal <strong>re</strong>gion concolorous with the<br />
distal lamina, but their distal leaf cross section is<br />
intermediate as is their leaf shape, deg<strong>re</strong>e <strong>of</strong> leaf torsion<br />
when dry, etc. Intermediate plants can be <strong>re</strong>adily found<br />
in Alaskan collections south <strong>of</strong> the Brooks Range and<br />
G<strong>re</strong>enland.<br />
Of the dried leaves <strong>of</strong> Tortella tortuosa var.<br />
arctica, some may appear stiff and straight, <strong>re</strong>sembling<br />
those <strong>of</strong> T. fragilis. The branch innovation-tufts on the<br />
sides <strong>of</strong> the stem appear like small dark claws or talons<br />
with the stiff limbs <strong>of</strong> the young leaves. Others may be<br />
perichaetial leaves protruding from among the<br />
vegetative leaves, appearing as stout glassy mucros. In<br />
T. fragilis, the leaves will be slightly thickened at the<br />
tips and most <strong>of</strong> the distal leaves will have lost their<br />
tips.<br />
The plants in similarly dense tufts <strong>of</strong> Tortella<br />
tortuosa var. tortuosa a<strong>re</strong> thinner (less foliose) when<br />
dry, the leaves mo<strong>re</strong> crisped-chaotic to the base <strong>of</strong> the<br />
stems, which a<strong>re</strong> also conspicuously felted with <strong>re</strong>d<br />
tomentum. Stems in tufts <strong>of</strong> var. arctica a<strong>re</strong> usually<br />
mo<strong>re</strong> <strong>re</strong>gimented and <strong>re</strong>gular in their leaf stance with<br />
only the young tips crisped, the tufts a<strong>re</strong> less open and<br />
mo<strong>re</strong> closely packed. Although they appear not<br />
tomentose, the tomentum is actually inconspicuous and<br />
hidden in the leaf bases. T. inclinata var. densa is<br />
similar to this, with tomentum hidden or <strong>re</strong>duced to<br />
nearly absent in well-developed forms.<br />
Stems <strong>of</strong> Tortella tortuosa var. arctica in tufts<br />
in the Arctic a<strong>re</strong> f<strong>re</strong>quently rigidly upright due to a<br />
varnish <strong>of</strong> what is perhaps cyanobacteria. The stems a<strong>re</strong><br />
so tightly packed that the<strong>re</strong> is no room for flexion<br />
except at the stem tips. The <strong>re</strong>gimented, tightly packed<br />
stems in orderly linear packets a<strong>re</strong> also found in Arctic<br />
specimens <strong>of</strong> Tortella fragilis—so dense as to be devoid<br />
<strong>of</strong> admixtu<strong>re</strong>s <strong>of</strong> other species.<br />
No species <strong>of</strong> Tortella so far studied from the<br />
North American Arctic have stem central strands except<br />
very ra<strong>re</strong>ly. Trichostomum arcticum Kaal. in the Arctic<br />
has a strong central strand, a useful character to<br />
distinguish it from specimens <strong>of</strong> Tortella tortuosa var.<br />
arctica when the<strong>re</strong> appear to be no diffe<strong>re</strong>ntiated<br />
marginal proximal cells. Trichostomum arcticum also<br />
has no quadrate papillose cells on the adaxial surface <strong>of</strong><br />
the costa, whe<strong>re</strong>as Tortella arctica does, for the most<br />
part. Trichostomum tenuirost<strong>re</strong>, on the other hand, has a<br />
variable central strand, sometimes even among sections<br />
<strong>of</strong> the same stem: the horizontal transition <strong>of</strong> distal<br />
laminal to proximal cells is approximately flat across<br />
the leaf, not at an oblique angle, and the leaf apex is<br />
f<strong>re</strong>quently not a long acumination, but one much<br />
shorter, arising above an abrupt contraction in the leaf<br />
blade forming small shoulders in the lamina just befo<strong>re</strong><br />
the apex.<br />
The thick habit <strong>of</strong> the var. arctica is<br />
occasionally seen in mo<strong>re</strong> southern latitudes: a<br />
specimen from Tennessee had leaves thickly covering
the stem with an apical coma, as did another from Iowa<br />
(Jackson County, along Brush C<strong>re</strong>ek east <strong>of</strong> And<strong>re</strong>w, on<br />
high limestone ledge, H. S. Conard, Oct. 13, 1945, NY).<br />
The Labrador specimen from Carroll Cove, J.<br />
A. Allen, 1882 (NY) cited by Crundwell and Nyholm as<br />
Tortella arctica and annotated by Crundwell<br />
demonstrated that the distinctions a<strong>re</strong> not as obvious as<br />
might be on first sight. The specimens had a <strong>re</strong>ddish<br />
cast, we<strong>re</strong> in dense, uniform sods, had thick-walled cells<br />
including proximal cells excepting a median a<strong>re</strong>a near<br />
the leaf insertion and a <strong>re</strong>latively indeterminate<br />
transition a<strong>re</strong>a between the papillose laminal cells and<br />
the clear proximal ones, the imp<strong>re</strong>ssion that the costa<br />
was broader than typical T. tortuosa var. tortuosa: yet<br />
the leaf shape was not that as illustrated for the variety<br />
(an inflated proximal a<strong>re</strong>a and a diffe<strong>re</strong>ntiated distal<br />
lamina), the margins we<strong>re</strong> undulate, the plants s<strong>of</strong>t and<br />
mo<strong>re</strong> contorted in the lower stem <strong>re</strong>gions, some <strong>of</strong> the<br />
proximal cells we<strong>re</strong> distinct and thin-walled, the stems<br />
we<strong>re</strong> not densely foliose, tomentum was clearly evident<br />
from the leaf bases. Perhaps the most decisive<br />
characteristic was the circular costa section with only<br />
two exposed ste<strong>re</strong>id cells. The specimen was var.<br />
tortuosa.<br />
A specimen from the Cape Parry was<br />
distinctive because the leaves we<strong>re</strong> long-subulate and<br />
whip-like, stiff and not e<strong>re</strong>ct but flexuose-circinate in<br />
broad arcs and hardly undulate, the tomentum hidden.<br />
The color was a dark, dull g<strong>re</strong>en, without any evidence<br />
<strong>of</strong> <strong>re</strong>ddness except in the lower part <strong>of</strong> the stem. The<br />
specimen was so peculiar that at first glance it appea<strong>re</strong>d<br />
to be a specimen <strong>of</strong> Tortella fragilis. The laminal cells<br />
we<strong>re</strong> thin-walled, the proximal ones distinctly set <strong>of</strong>f<br />
from them in color and smoothness, but we<strong>re</strong> as thick<br />
walled. The leaf shape distal to the proximal cell <strong>re</strong>gion<br />
was abruptly set <strong>of</strong>f but ext<strong>re</strong>mely long with very long<br />
mucros. It appea<strong>re</strong>d to be Tortella tortuosa var. tortuosa<br />
except for the peculiar elongate leaf cross-section and<br />
was ultimately determined to be var. arctica. The leaf<br />
section appea<strong>re</strong>d <strong>re</strong>niform, rather than nearly circular as<br />
in var. tortuosa, appa<strong>re</strong>ntly due to the number <strong>of</strong><br />
butt<strong>re</strong>ssing or supporting cells in the costa adjoining the<br />
lamina.<br />
G<strong>re</strong>enland: west, on dry basaltic rock, Nugssuaq Pen:<br />
Marrait, 70°30'N, 54°12'W, Sept. 4, 1956, K.<br />
Holmen 14.806 (NY); head <strong>of</strong> a fjord S <strong>of</strong><br />
Marmorilik 71°06'N, 51°12'W; Nuggsuaq<br />
Peninsula: Ikorfat, 70°45'N, 53°07'W; N.<br />
G<strong>re</strong>enland, Heilprin Land, Brönlund Fjord<br />
82°10'N, 31'W.<br />
B.C.: ca. 3 mi. beyond N. end <strong>of</strong> Summit Lake, cliff<br />
shelf, W.B. Sch<strong>of</strong>ield 66186, July 23, 1977<br />
(DUKE).<br />
Nfld.: South Branch Condroy River, St. George's, Port<br />
au Port; about 47°54'N, 58°58'W, July 2–4,<br />
1949, R. Tuomikoski 2432 (MICH).<br />
N.W.T.: Axel Heiberg Island, E <strong>of</strong> alluvials <strong>of</strong> Crusoe<br />
River 79°23–24'N, 91°01'07"W, in peat, ca, 50<br />
m., June 20, 1967, M. Kuc M204 (NY); Baffin<br />
21<br />
Island: Head <strong>of</strong> Clyde Inlet, 1950, Baird<br />
Expedition, P. Danse<strong>re</strong>au 500820–0254 (NY).<br />
Yukon: alpine communities N <strong>of</strong> Carpenter Lake, 4000',<br />
Wernecke Mtns, 64°33'N, 135°07'W, July 24,<br />
1972, Scotter 17929 (NY).<br />
Colo.: Clear C<strong>re</strong>ek Co., dry rocky tundra below<br />
Argentine Pass, 13,000 ft. (3940 m), 7 miles<br />
SSW <strong>of</strong> Georgetown, Aug. 28, 1981, F. J.<br />
Hermann 29063 (NY); Boulder; Larimer;<br />
Summit.<br />
Maine: Somerset Co., ledges by Falls <strong>of</strong> the Carrabasset<br />
River, near Anson, July 21, 1896, J. Franklin<br />
Collins 1311 (NY) (perichaetiate plant).<br />
4c. TORTELLA TORTUOSA VAR. FRAGILIFOLIA<br />
Plate 6<br />
Tortella tortuosa var. fragilifolia (Jur.) Lindb., Laubm.<br />
Deutschl. 1: 605. 1888.<br />
Barbula tortuosa var. fragilifolia Jur.,<br />
Laubmfl. Öst. Ungarn 123. 1882.<br />
Tortella fragilifolia (Jur.) Roth, Hedwigia 49:<br />
218. 7 f. 2. 1910.<br />
Tortella tortuosa fo. fragilifolia (Jur.) Monk.,<br />
Laubm. Eur. 270. 1927.<br />
Trichostomum tortuosum var. fragilifolium<br />
(Jur.) Dix., Stud. Handb. Brit. Moss.<br />
221. 1896.<br />
Barbula tortuosa var. pseud<strong>of</strong>ragilis Thér.,<br />
Rev. Bryol. 25: 20. 1898.<br />
Leaves in simple spirals or once circinate when dry,<br />
appearing firm or rigid, laminae <strong>of</strong>ten fragile, erose, leaf<br />
tips <strong>of</strong>ten absent; distal laminal cells variable: (6–)7–<br />
10(–17) µm, inconspicuously undulate, especially when<br />
dry; leaf cross section with bistratose a<strong>re</strong>as beside the<br />
costa, the lamina ir<strong>re</strong>gularly bistratose in patches, costa<br />
occasionally appearing undiffe<strong>re</strong>ntiated in apical <strong>re</strong>gion<br />
<strong>of</strong> the leaf, adaxial ste<strong>re</strong>id layer occasionally<br />
disappearing toward the apex, epidermal layer<br />
continuous.<br />
Herbaria examined: BUF, CANM, MICH, NY,<br />
NYS, UBC.<br />
The year after Haring's t<strong>re</strong>atment <strong>of</strong> the North<br />
American species <strong>of</strong> Tortella (1938) appea<strong>re</strong>d, she<br />
collected a curious specimen in a soapstone quarry on<br />
rock from the town <strong>of</strong> Newfane, Vermont, whe<strong>re</strong> A. J.<br />
Grout lived. This was a rather peculiar example <strong>of</strong><br />
Tortella and she sent it to Grout and to H. N. Dixon in<br />
England for verification. Both men confirmed the plant<br />
to be Tortella nitida and, as such, it ente<strong>re</strong>d the ongoing<br />
tradition in the literatu<strong>re</strong> that this species occurs in<br />
North America (see discussion below under Tortella<br />
nitida).<br />
USA, Vermont: town <strong>of</strong> Newfane, soapstone<br />
quarry, on rock in mo<strong>re</strong> or less open woods, Aug., 1939,<br />
Inez M. Haring, s.n. "checked by Dr. A. J. Grout & H.<br />
N. Dixon" (NY; duplicate CANM). The CANM<br />
specimen was annotated as Tortella tortuosa by K.
Holmen, Sept. 59 (the<strong>re</strong> a<strong>re</strong> no mixtu<strong>re</strong>s with other<br />
species).<br />
A second collection <strong>of</strong> nearly identical material<br />
was discove<strong>re</strong>d in Quebec, determined by R. T.<br />
Wa<strong>re</strong>ham as Tortella nitida. Wa<strong>re</strong>ham did the<br />
t<strong>re</strong>atments <strong>of</strong> Pterygoneurum Jur. and Pottia (Reichenb.)<br />
F rnr. for Grout's North American moss flora (1939):<br />
Quebec, Mont Commis, St-Donat de Rimouski,<br />
rocher calcai<strong>re</strong>, 2-7-42, Ernest Lepage 3412 (MT),<br />
being mixed with Myu<strong>re</strong>lla julacea, Encalypta<br />
st<strong>re</strong>ptocarpa and Hypnum cup<strong>re</strong>ssiforme. This was also<br />
annotated by Kuc in 1968 as Tortella tortuosa: "T.<br />
nitida is a critical species, this material doubtfully<br />
belongs to this taxon.") This collection also contained<br />
plants <strong>of</strong> T. alpicola (discussed below). This specimen<br />
may be one basis for the Quebec citation <strong>of</strong> T. nitida in<br />
the Canadian checklist <strong>of</strong> I<strong>re</strong>land et al. (1987).<br />
This Quebec specimen had setae and capsules,<br />
most <strong>of</strong> which, due to their age, no longer <strong>re</strong>tained their<br />
peristomes or spo<strong>re</strong>s. The single capsule with a batte<strong>re</strong>d<br />
peristome showed that to be eroded and quite short,<br />
short enough to <strong>re</strong>semble that <strong>of</strong> Tortella flavovi<strong>re</strong>ns or<br />
T. nitida. The setae we<strong>re</strong> 1 cm long, the capsules 1.2–2<br />
mm; spo<strong>re</strong>s nearly smooth (10–)12(–14) µm.<br />
Neither <strong>of</strong> these inte<strong>re</strong>sting collections is in<br />
fact <strong>re</strong>ferable to Tortella nitida, yet, except for the stem<br />
central strand in the Vermont specimen, they we<strong>re</strong><br />
nearly identically distinctive. Both had ext<strong>re</strong>mely fragile<br />
leaf apices such that nearly all we<strong>re</strong> absent, the<strong>re</strong> we<strong>re</strong><br />
leaf cross-section ir<strong>re</strong>gularities (bistratose a<strong>re</strong>as<br />
juxtacostally), both had <strong>re</strong>latively broad leaves that we<strong>re</strong><br />
rather shortly mucronate and had quadrate cells on the<br />
adaxial surface <strong>of</strong> the costa completely through to the<br />
leaf apex. The adaxial ste<strong>re</strong>id band disappea<strong>re</strong>d distally,<br />
but the adaxial epidermal layer <strong>re</strong>mained intact, an<br />
unusual characteristic for species <strong>of</strong> the genus.<br />
Additional specimens with similar<br />
characteristics we<strong>re</strong> discove<strong>re</strong>d during the course <strong>of</strong> the<br />
p<strong>re</strong>sent study in Michigan material at higher elevations<br />
in the northern part <strong>of</strong> the state. These include:<br />
Michigan: Baraga Co. soil in c<strong>re</strong>vices <strong>of</strong> basalt outcrop<br />
on bank <strong>of</strong> Silver River Falls, ca. 6 miles ENE <strong>of</strong><br />
L'Anse, July 9, 1970, F. J. Hermann 23173 (MICH);<br />
Keweenaw Co., open ground on summit <strong>of</strong> mountain,<br />
Mt. Lookout, May 14, 1949, Charles D. Richards 38<br />
(MICH); also Mt. Bohemia, July 18, 1950, Charles D.<br />
Richards 212 (MICH); also gravelly field, site <strong>of</strong> old<br />
schoolhouse, Copper Harbor, Aug. 30, 1960, F. J.<br />
Hermann 16352 (MICH); Ontonagon Co., talus blocks,<br />
Porcupine Mountains, G. E. Nichols & W. C. Stee<strong>re</strong>,<br />
Aug. 20–27, 1935 (MICH).<br />
The stem central strand so evident in Haring's<br />
Vermont specimen was absent in additional collections.<br />
Mo<strong>re</strong> specimens then came to light that we<strong>re</strong> not fragile,<br />
that had large laminal cells (to 17 mm) or else tiny,<br />
crazed ones. The quadrate, papillose adaxial costal cells<br />
may disappear in the apex and <strong>re</strong>tain the adaxial ste<strong>re</strong>id<br />
band. But the many independently variable characters<br />
had one element in common: they appea<strong>re</strong>d to be<br />
22<br />
variations on the basic set <strong>of</strong> characters for Tortella<br />
tortuosa.<br />
One similar specimen from central Alaska had<br />
leaves sufficiently e<strong>re</strong>ct and narrowed as to <strong>re</strong>semble<br />
Tortella fragilis. On dissection, it appea<strong>re</strong>d that the<br />
narrowed leaves we<strong>re</strong> actually typical leaves <strong>of</strong> T.<br />
tortuosa, but so inrolled as to be tubulose in crosssection,<br />
hence its narrow appearance when dry. In<br />
addition, the adaxial epidermal layer <strong>re</strong>mained intact<br />
throughout the leaf-length, but the adaxial ste<strong>re</strong>id layer<br />
was absent. Otherwise, in all other macro- and<br />
microscopic characters, the plants we<strong>re</strong> T. tortuosa<br />
("moist, rather sunny seepage on S face outcrop in<br />
tundra," (65°23'N, 145°57'W, Norris 54115, NY).<br />
A hitherto European taxon, Tortella tortuosa<br />
var. fragilifolia (Jur.) Limpr. was examined in the light<br />
<strong>of</strong> this variability and all <strong>of</strong> the above specimens<br />
conform to descriptions and specimens <strong>of</strong> that variety.<br />
The type <strong>of</strong> var. fragilifolia has no stem central strand<br />
and also possesses a central groove on the adaxial<br />
surface <strong>of</strong> the costa in the distal portion <strong>of</strong> the leaf,<br />
exposing the adaxial ste<strong>re</strong>ids. This particular specimen<br />
is so similar to the typical variety as to initially cast<br />
doubt on its distinctiveness.<br />
Juratzka (1882) originally described the variety<br />
fragilifolia as sparsely tomentose, the leaf apices fragile,<br />
the costa whitish on the back and strongly shining.<br />
"Diese Form verh„lt sich zu der gewöhnlichen wie<br />
[Tortella] nitida zu [T.] inclinata und kann leicht mit T.<br />
fragilis verwechselt werden," by which I understand<br />
him to mean that the variety stands in <strong>re</strong>lation to the<br />
typical variety as T. nitida does to T. inclinata. The<br />
variety is easily confused with T. fragilis, having a<br />
setaceous, deciduous (but non-propaguloid) apex.<br />
Among the substrates he noted for the variety we<strong>re</strong><br />
sunny calca<strong>re</strong>ous rocks, on t<strong>re</strong>es (an Baumen bei<br />
Gostling) and sandstone walls.<br />
Dema<strong>re</strong>t and Castagne (1964), for Belgium,<br />
separate the variety fragilifolia from the typical one by<br />
the shorter leaves, 1.4–5 mm, mo<strong>re</strong> narrow and fragile,<br />
the leaves less crisped in the dry state, the leaf point<br />
mo<strong>re</strong> shortly acuminate, the stem without tomentum.<br />
This is an excellent description for North American<br />
material in general. However, leaves in both American<br />
and European material <strong>of</strong> this variety <strong>re</strong>ach the longest<br />
length the typical variety can attain. The<strong>re</strong> occur, as<br />
well all deg<strong>re</strong>es <strong>of</strong> tomentum on the stem, and lengths<br />
<strong>of</strong> mucro. The European authors suggest that the<br />
distribution <strong>of</strong> the variety is the same as the species<br />
whe<strong>re</strong>as it seems to be associated with upland<br />
(subalpine) stations in North America.<br />
Albertson (1946), in his key to the Swedish<br />
species, indicated that the var. fragilifolia was the same<br />
as the var. tortuosa except that the leaves we<strong>re</strong> less<br />
strongly spiralled, less undulate and strongly fragile.<br />
Additional named material from Europe was<br />
examined. The most stable character that unites North<br />
American variability with the European is the<br />
anomalous character <strong>of</strong> the leaf cross section tending<br />
toward bistratose juxtacostal <strong>re</strong>gions that may penetrate
into the costa section. Sometimes the adaxial ste<strong>re</strong>id<br />
layer is missing toward the apex and sometimes the<br />
quadrate, papillose cells on the adaxial surface <strong>of</strong> the<br />
costa extend completely to the leaf apex. The lamina<br />
may have bistratose patches; some lumina can have<br />
diagonal cross-walls; in one section the<strong>re</strong> was a<br />
bistratose a<strong>re</strong>a at the leaf margin and in many these<br />
variations we<strong>re</strong> not symmetrical across the leaf blade,<br />
but occur<strong>re</strong>d on only one lamina. Occasionally the costa<br />
itself becomes undiffe<strong>re</strong>ntiated.<br />
Sections in the distal leaf mo<strong>re</strong> than any other<br />
single character a<strong>re</strong> critical or fundamental to the<br />
determination <strong>of</strong> the variety. The var. fragilifolia, then,<br />
is essentially a cryptic variety in the sense that the<br />
definitive characters derive mostly from the anatomy <strong>of</strong><br />
the leaf. It is this variation in Tortella tortuosa as well<br />
as the characteristics <strong>of</strong> T. alpicola that together have<br />
contributed to the concept <strong>of</strong> T. nitida in North America<br />
(see discussion below). Also numerous specimens in<br />
American herbaria identified as T. tortuosa with a query<br />
can be <strong>re</strong>fer<strong>re</strong>d to this variety. Recognition <strong>of</strong> this<br />
variety in North America should contribute to stability<br />
in the determination <strong>of</strong> specimens.<br />
Plants a<strong>re</strong> as in the typical variety: in dense<br />
tufts, interwoven at the stem apices when dry by the<br />
contortion <strong>of</strong> the leaves, with the same coloration;<br />
although the stems in section appear rather larger than<br />
typically, a distinctive central strand is ra<strong>re</strong>ly p<strong>re</strong>sent.<br />
The stems usually have a dense rufous tomentum. The<br />
leaves differ by being little or not undulate or crisped<br />
when dry, but may be undulate when wet; they a<strong>re</strong><br />
typically only once circinate and without the delicate<br />
appearance <strong>of</strong> the typical variety. The leaves, within the<br />
range <strong>of</strong> variation <strong>of</strong> the species, tend to be somewhat<br />
shorter and broadly lanceolate in the proximal twothirds<br />
(not setaceous), and the laminae can seem to<br />
deteriorate and appear fragile; yet they may also be<br />
ext<strong>re</strong>mely long and narrow (setaceous), especially in<br />
western North American populations.<br />
While some leaves have the typical long,<br />
glossy mucro <strong>of</strong> var. tortuosa, in others the mucro is just<br />
a small tip surmounting what appears to be a<br />
prolongation <strong>of</strong> the leaf apex into a canaliculate<br />
extension, this f<strong>re</strong>quently broken. Inf<strong>re</strong>quently some<br />
apices have a solid and circular form which, like a<br />
finger, together with a vague border <strong>of</strong> cells f<strong>re</strong>e <strong>of</strong><br />
papillae, show a striking affinity with T. fragilis. That<br />
the abaxial surface <strong>of</strong> the costa in the apical portion <strong>of</strong><br />
the leaf is <strong>of</strong>ten roughened with low papillae is also<br />
indicative <strong>of</strong> the propaguloid modifications <strong>of</strong> T.<br />
fragilis, as is the tendency toward undiffe<strong>re</strong>ntiated cells<br />
in the costa in the apical <strong>re</strong>gion.<br />
The leaf midsections occasionally seem fragile<br />
or brittle, but also it is f<strong>re</strong>quently only the leaf tips that<br />
a<strong>re</strong> prone to b<strong>re</strong>akage. These appear to taper into thinner<br />
apical limbs, especially in some leaves, facilitating this<br />
condition. In some collections, many <strong>of</strong> the leaf apices<br />
a<strong>re</strong> broken <strong>of</strong>f (absent). The leaves may or may not have<br />
a vague display <strong>of</strong> mo<strong>re</strong> or less elongate smooth cells on<br />
the distal margins, this contributing to a mo<strong>re</strong> rigid and<br />
23<br />
e<strong>re</strong>ct leaf apex, and it hints at the deciduous natu<strong>re</strong> <strong>of</strong><br />
the apex, on analogy with Tortella rigens and mo<strong>re</strong><br />
conspicuously in T. fragilis.<br />
The character <strong>of</strong> the costa is f<strong>re</strong>quently<br />
diffe<strong>re</strong>nt from that <strong>of</strong> the typical variety: the adaxial<br />
epidermis can be <strong>re</strong>tained continuously through to the<br />
apex without a central groove in the distal <strong>re</strong>gion: the<br />
adaxial ste<strong>re</strong>id band can disappear distally. Occasionally<br />
the quadrate cells a<strong>re</strong> lost in the far distal portion <strong>of</strong> the<br />
leaf, but the quadrate cell layer usually extends further<br />
towards the apex than in the typical variety. In some<br />
cases the abaxial ste<strong>re</strong>ids become subste<strong>re</strong>id and the<br />
enti<strong>re</strong> costa appears undiffe<strong>re</strong>ntiated. Note that both the<br />
epidermal cells and the guide cells should be p<strong>re</strong>sent in<br />
the leaf cross section to assess whether the adaxial<br />
ste<strong>re</strong>id layer has disappea<strong>re</strong>d. If the guide cells a<strong>re</strong> the<br />
only cells at the adaxial surface <strong>of</strong> the leaf, the section is<br />
made too far into the ext<strong>re</strong>me apex to be diagnostic.<br />
The laminal cells in the distal half <strong>of</strong> the leaf<br />
can become very small and obscu<strong>re</strong>: 5–7 µm on average<br />
with transversely flattened marginal cells. The laminal<br />
cells may also be very large, <strong>re</strong>aching 17 µm (the case<br />
in Macoun 605; see below). The leaf cross section also<br />
f<strong>re</strong>quently <strong>re</strong>sembles a smaller celled version <strong>of</strong> Tortella<br />
rigens: small marginal cells grading into larger ones<br />
beside the costa, the<strong>re</strong> being a bi-to multi-stratose a<strong>re</strong>a<br />
juxtacostally. The proximal cells may be thicker walled<br />
than the typical lax cells, the distal laminal cells may<br />
also be somewhat thicker-walled. The Quebec specimen<br />
cited above is the only example seen so far <strong>of</strong> the var.<br />
fragilifolia in fruit.<br />
Dixon (1924) wrote that European Tortella<br />
tortuosa var. fragilifolia is very close in <strong>re</strong>semblance to<br />
T. nitida. This is further evidence at least as to fragility<br />
that the var. fragilifolia described he<strong>re</strong> is indeed within<br />
the variation <strong>of</strong> the var. fragilifolia in Europe. Dixon<br />
described the var. fragilifolia in England as growing in<br />
"short small tufts; leaves smaller [than in the typical<br />
variety], shorter, less finely tapering, very fragile...,<br />
leaves when dry less strongly contorted, but mo<strong>re</strong><br />
closely incumbent." In specimens seen from both<br />
Europe and North America, the var. fragilifolia may<br />
have leaves fully as long or even longer than Tortella<br />
fragilis or T. tortuosa and the tufts in which they grow<br />
a<strong>re</strong> neither <strong>re</strong>latively short nor small.<br />
Dixon's statement that the var. fragilifolia<br />
grows on "exposed alpine rocks" seems consistent with<br />
the tendency <strong>of</strong> North American var. fragilifolia to<br />
favor higher elevations and rocky substrates.<br />
Throughout Dixon's t<strong>re</strong>atment <strong>of</strong> Tortella (as<br />
Trichostomum) the<strong>re</strong> is a deg<strong>re</strong>e <strong>of</strong> uncertainty about<br />
species delimitations concerning T. inclinata, T. fragilis,<br />
T. nitida and the varieties <strong>of</strong> T. tortuosa. Dixon, upon<br />
studying numerous puzzling variants <strong>of</strong> T. tortuosa,<br />
postulated that the var. fragilifolia and Boulay's var.<br />
rigidum (= T. tortuosa var. rigida (Boul.) Limpr.) "a<strong>re</strong><br />
not mo<strong>re</strong> than dwarf and somewhat starved forms<br />
induced by their habitat, which is usually on exposed<br />
mountain rocks." He noted that while T. nitida is fragile
in the lamina, the var. fragilifolia is usually broken at<br />
the leaf tip.<br />
Dixon (1924) was also not su<strong>re</strong> <strong>of</strong> the<br />
distinction <strong>of</strong> Tortella fragilis from T. tortuosa. He<br />
would have liked to have been definite but, "I have,<br />
however, <strong>re</strong>ceived specimens from two or th<strong>re</strong>e<br />
localities in Labrador showing a distinct approach to [T.<br />
tortuosa]; the leaves on some <strong>of</strong> the plants, and even the<br />
lower leaves on some stems in which the distal ones a<strong>re</strong><br />
quite typical, being strongly contorted when dry, crisped<br />
and undulate at the margin, and when moist slightly<br />
flexuose and undulate; hardly, indeed, to be <strong>re</strong>cognised<br />
from the var. fragilifolia...except by the leaves<br />
somewhat firmer, the very shining nerve and the<br />
p<strong>re</strong>sence (usually) <strong>of</strong> some rigid and less curved<br />
leaves." He speculated that T. fragilis would be found to<br />
be close to T. tortuosa "by intermediate forms."<br />
Polunin (1947), when <strong>re</strong>porting Tortella<br />
fragilis for the Canadian Eastern Arctic, quoted the<br />
same lines from Dixon (1924), adding "This puzzling<br />
situation that Mr. Dixon has so ably elucidated is to be<br />
found also in the specimens from Baffin Island"<br />
although some <strong>of</strong> these specimens, upon examination,<br />
may turn out to be T. tortuosa var. arctica.<br />
Tortella tortuosa var. fragilifolia in North<br />
America appears to be a montane and bo<strong>re</strong>al taxon. The<br />
var. fragilifolia in North America is appa<strong>re</strong>ntly not in<br />
montane elevations much south <strong>of</strong> the latitude <strong>of</strong> the<br />
Canadian border with the conterminous United States.<br />
TORTELLA NITIDA IN NORTH AMERICA<br />
Sources <strong>of</strong> North American <strong>re</strong>ports <strong>of</strong> Tortella nitida<br />
perhaps began with Renauld and Cardot (1889: 99) (as<br />
Trichostomum nitidum) "United States, without locality,<br />
collected by James, communicated by Mr. Besche<strong>re</strong>lle."<br />
Barnes (1897: 275–276) next <strong>re</strong>ported the<br />
species, quoting Renauld and Cardot and basing his<br />
description on Limpricht (1890, 1: 581) whe<strong>re</strong> the<br />
description <strong>of</strong> the proximal cells indicates their being<br />
"less sharply marked <strong>of</strong>f from chlorophyllose cells."<br />
Assuming James, <strong>of</strong> the Renauld and Cardot quote, to<br />
be Thomas Potts James (1803–1882), a <strong>re</strong>quest was<br />
made to the Farlow Herbarium for a specimen that<br />
might cor<strong>re</strong>spond, but without success. A James<br />
specimen at NY collected by him in Canada, July 1850,<br />
was Tortella tortuosa var. tortuosa.<br />
Next, the<strong>re</strong> is the exsiccat specimen in the<br />
Canadian Musci by John Macoun, number 605, labeled<br />
as Barbula nitida. In 1892, Macoun and N. C. Kindberg<br />
published the label data (number 196, p. 52). Kindberg<br />
(1897) affirmed its occur<strong>re</strong>nce ("Can.: Macoun.),<br />
p<strong>re</strong>sumably from Macoun's exsiccat number 605.<br />
Macoun 605 is labeled as Barbula nitidum [sic] (Lindb.)<br />
Jur., <strong>of</strong> the Canadian Musci series, "on wet earth at<br />
Hector, Rocky Mountains, B.C. [British Columbia,<br />
Canada], Aug. 14th, 1890" and is Tortella tortuosa var.<br />
fragilifolia (one specimen at FH, two others at NY). It is<br />
as tall as the typical variety gets, has a broad stem<br />
section but no central strand. Some apices a<strong>re</strong> deciduous<br />
and the<strong>re</strong> is conspicuous fragility <strong>of</strong> the lamina. The<br />
24<br />
crucial juxtacostal bistratose character <strong>of</strong> the leaf<br />
cross section is p<strong>re</strong>sent. The cells <strong>of</strong> the lamina a<strong>re</strong><br />
unusual for the species, on some leaves <strong>re</strong>gularly ca. 14<br />
µm, some even to 17 µm in diameter, with distal<br />
proximal cells thick-walled and porose. Some leaves on<br />
the same stem have adaxial quadrate cells covering the<br />
costa nearly to the apex, in others the adaxial surface <strong>of</strong><br />
the costa is exposed in a narrow groove from base to<br />
apex.<br />
Subsequent <strong>re</strong>ports <strong>of</strong> Tortella nitida include<br />
Haring's (1938) t<strong>re</strong>atment in Grout's moss flora <strong>of</strong> North<br />
America, Flower's t<strong>re</strong>atment for the state <strong>of</strong> Utah<br />
(1973), Ketchledge's publication on the moss flora <strong>of</strong><br />
New York State (1957), Stee<strong>re</strong> and Scotter's (1978)<br />
<strong>re</strong>port for the Nahanni P<strong>re</strong>serve, in the Mackenzie<br />
District <strong>of</strong> the Northwest Territories, and the <strong>re</strong>cent<br />
checklist <strong>of</strong> Canadian mosses (I<strong>re</strong>land et al. 1987).<br />
Haring (1938) cited Macoun's number 605 in<br />
the Canadian Musci as Tortella nitida; also a specimen<br />
from Montana in NY, and one by Homer House, a<br />
specimen from Harris Lake, New York. Haring and<br />
perhaps Grout, we<strong>re</strong> strongly influenced in their<br />
expectations by the Macoun specimen. This was at a<br />
time when it was not yet accepted that some <strong>of</strong> Macoun<br />
and Kindberg's determinations we<strong>re</strong> perhaps doubtful.<br />
Kindberg's determinations <strong>of</strong> Macoun's specimens<br />
"we<strong>re</strong> <strong>of</strong>ten hasty and consequently wrong and<br />
Macoun's own determinations we<strong>re</strong> <strong>of</strong>ten based on<br />
superficial study and thus a<strong>re</strong> open to doubt" (Sch<strong>of</strong>ield<br />
1965), and yet Besche<strong>re</strong>lle and Dixon also made similar<br />
independent determinations.<br />
Examination <strong>of</strong> the specimen <strong>of</strong> Tortella nitida<br />
that Haring cited for Lake Harris (New York, Essex Co.,<br />
Newcomb, surface <strong>of</strong> boulder on sho<strong>re</strong> (perichaetiate:<br />
without sporophytes), July 10, 1927, H.D.House (NYS),<br />
shows this specimen also to be Tortella tortuosa var.<br />
fragilifolia. The Harris Lake specimen was fragile in<br />
some stems, but on the whole seems mo<strong>re</strong> typical <strong>of</strong> T.<br />
tortuosa than most examples <strong>of</strong> the variety fragilifolia<br />
(it had no stem central strand). The leaves on some<br />
stems, however, we<strong>re</strong> mo<strong>re</strong> broadly lanceolate with<br />
larger distal laminal cells (to 12 µm). Some <strong>of</strong> the leaf<br />
cross sections showed some bistratose a<strong>re</strong>as near the<br />
costa in the distal median portion <strong>of</strong> the leaf.<br />
The Harris Lake specimen showed no<br />
annotation by Haring or Grout. The<strong>re</strong> was a query on<br />
the label, and the note, "Doubtful !E.H.K" [Edwin H.<br />
Ketchledge] written on the packet. Ketchledge's<br />
subsequent publication on the moss flora <strong>of</strong> New York<br />
State (1957) listed Tortella nitida for the New York<br />
flora, but in the <strong>re</strong>vised edition (Ketchledge 1980), the<strong>re</strong><br />
was no citation <strong>of</strong> that species.<br />
Another specimen <strong>of</strong> the var. fragilifolia, from<br />
New York on limestone pavement in Jefferson Co. in<br />
association with Tortella rigens, is cited below in the<br />
t<strong>re</strong>atment <strong>of</strong> that species.<br />
Haring's third <strong>re</strong>p<strong>re</strong>sentative specimen was<br />
from Montana at NY. A specimen from Montana<br />
collected by R. S. Williams, 329 at NY was determined<br />
he<strong>re</strong> to be Tortella alpicola (see discussion <strong>of</strong> this
specimen under that species). The<strong>re</strong> is no indication on<br />
the sheet that Inez Haring saw this, but the<strong>re</strong> is an<br />
annotation on the sheet "= Tortella!! A. J. G. Probably<br />
T. nitida (Lindb.) Broth." The annotation appears to be<br />
by A. J. Grout. If this is one <strong>of</strong> the specimens cited by<br />
Haring in her t<strong>re</strong>atment <strong>of</strong> the genus, then her (and<br />
possibly Grout's) concept <strong>of</strong> North American T. nitida is<br />
that <strong>of</strong> T. alpicola, in part (the specimen is sterile).<br />
A specimen (MNA, FH) determined by Haring<br />
as "possibly Tortella nitida" collected in Arizona, was<br />
also T. alpicola. She noted on the packet that the plants<br />
had central strands, strongly crisped leaves, which we<strong>re</strong><br />
much broken at tips and we<strong>re</strong> sometimes undulate.<br />
The large size <strong>of</strong> the two specimens <strong>of</strong> var.<br />
fragilifolia is in marked contrast to the tiny dimensions<br />
<strong>of</strong> T. alpicola in the four specimens on which she based<br />
her concept <strong>of</strong> T. nitida, but it is clear that the<br />
description <strong>of</strong> T. nitida by Haring (1938) included a<br />
conflation <strong>of</strong> T. alpicola and T. tortuosa var. fragilifolia.<br />
The var. fragilifolia occurs throughout the middle range<br />
<strong>of</strong> the var. tortuosa, and the range <strong>of</strong> T. alpicola is<br />
decidedly western (see discussion under that species).<br />
It is truly extraordinary that in this context the<br />
specimen from Quebec mentioned above, identified by<br />
Warham as Tortella nitida, actually contained two<br />
separate Tortella entities: growing beside the var.<br />
fragilifolia in this specimen was T. alpicola: a<br />
significant range extension, indeed, from its western and<br />
Arctic populations and p<strong>re</strong>sumably associated with a<br />
southern extension <strong>of</strong> a bo<strong>re</strong>al-Arctic floristic element.<br />
The tiny T. alpicola had its typical stem central strand,<br />
the var. fragilifolia plants did not. The single specimen<br />
determined by S. Flowers as Tortella nitida and<br />
collected in Utah from Duchesne county turned out to<br />
be T. alpicola (see Flowers 1973).<br />
As discussed under Tortella alpicola above,<br />
citations in the checklist <strong>of</strong> the mosses <strong>of</strong> Canada for the<br />
p<strong>re</strong>sence <strong>of</strong> T. nitida we<strong>re</strong> derived from the literatu<strong>re</strong>.<br />
Those from Quebec a<strong>re</strong> most certainly Tortella tortuosa<br />
var. tortuosa or var. fragilifolia. For example, another<br />
specimen at CANM (Quebec, Beauce Co., Beauceville,<br />
Apr. 20, 1939, Br. Marie-Anselm 2875 (CANM)<br />
determined by the collector as T. nitida is T. tortuosa<br />
var. tortuosa. The Macoun specimens (Canadian Musci<br />
605) on which the British Columbia citation may be<br />
based a<strong>re</strong> Tortella tortuosa var. fragilifolia. The Stee<strong>re</strong><br />
and Scotter (1978) specimen <strong>of</strong> Tortella nitida cannot<br />
be located, but the<strong>re</strong> was doubt cast on this<br />
determination when it was published (see discussion<br />
under T. nitida below).<br />
25<br />
Tortella alpicola differs from T. tortuosa var.<br />
fragilifolia by its small size, large leaf cells (averaging<br />
14 µm) and development in sterile material <strong>of</strong> a<br />
caducous propagulum at the leaf apex: primarily in the<br />
same characters that distinguish it from typical T.<br />
tortuosa. What brings Tortella nitida strongly to mind<br />
when viewing Haring's Vermont specimens is the nearly<br />
complete absence <strong>of</strong> leaf tips in the collections. The<br />
distinct central strand happens he<strong>re</strong> to be me<strong>re</strong>ly one <strong>of</strong><br />
the ra<strong>re</strong> instances <strong>of</strong> its occur<strong>re</strong>nce in the species, s.l..<br />
The eastern North American plants differ from<br />
European T. nitida by the long-lanceolate to nearly<br />
subulate leaf, not ligulate (not <strong>re</strong>sembling T. humilis),<br />
the rather consistently long mucro, the fragility confined<br />
to the leaf apex rather than throughout the leaf, and the<br />
distinct and abruptly diffe<strong>re</strong>ntiated proximal cells rather<br />
than the gradual transition in the European plant. The<br />
cross section <strong>of</strong> the costa <strong>of</strong> true T. nitida has a convex<br />
adaxial silhouette, massive abaxial and adaxial ste<strong>re</strong>id<br />
layers and a striking adaxial palisade <strong>of</strong> papillose<br />
epidermal cells. This <strong>re</strong>sembles no Tortella species in<br />
North America; it is mo<strong>re</strong> like Pseudosymblepharis<br />
schimperiana <strong>of</strong> Latin America in this <strong>re</strong>spect.<br />
Another featu<strong>re</strong> distinguishing the Vermont<br />
specimens from Tortella nitida is that they a<strong>re</strong> stiffly<br />
e<strong>re</strong>ct when dry and a<strong>re</strong> only twisted in the apices <strong>of</strong> the<br />
leaves at the apices <strong>of</strong> the stems, such as actually <strong>re</strong>tain<br />
their apices. Tortella nitida has stiffly incurved leaves<br />
when dry throughout the stem.<br />
The V-shaped <strong>re</strong>gion <strong>of</strong> proximal leaf cells <strong>of</strong><br />
this variety place the Vermont specimens clearly in<br />
Tortella, as no other genus in North America has this<br />
characteristic. This featu<strong>re</strong> distinguished the material<br />
from any species <strong>of</strong> the genus Trichostomum, yet the<br />
specimens <strong>re</strong>semble that genus in two characters: the<strong>re</strong><br />
is an elaborate, unambiguous stem central strand, and<br />
the surface <strong>of</strong> the costa is completely cove<strong>re</strong>d with<br />
quadrate, papillose cells, whe<strong>re</strong> the<strong>re</strong> is no exposu<strong>re</strong><br />
whatsoever. Tortella tortuosa has an adaxial groove<br />
whe<strong>re</strong> the ste<strong>re</strong>id cells a<strong>re</strong> exposed to no mo<strong>re</strong> than two<br />
ste<strong>re</strong>id cells and these only at the distal end <strong>of</strong> the leaf.<br />
Most other taxa in the United States lose the adaxial<br />
epidermal layer in the apex <strong>of</strong> their leaves except for<br />
Tortella alpicola. In that species the quadrate cells <strong>of</strong><br />
the epidermal layer also persist while the adaxial ste<strong>re</strong>id<br />
layer disappears and in fertile stems the<strong>re</strong> is no ste<strong>re</strong>id<br />
layer at all in the distal portion <strong>of</strong> the leaf—<strong>re</strong>miniscent<br />
<strong>of</strong> the leaf section <strong>of</strong> species <strong>of</strong> the South American<br />
genus St<strong>re</strong>ptocalypta or the Antarctic Sarconeurum.<br />
KEY TO NORTH AMERICAN TORTELLAE WITH DECIDUOUS APICES<br />
1. Stem with central strand, leaf cells generally 14 µm, quadrate papillose cells on the adaxial surface <strong>of</strong> the costa;<br />
very small plants to 1.5 cm; with distinctive caducous propagula at modified leaf apex when sterile, plants <strong>of</strong> the<br />
West, disjunct to Quebec . . . . Tortella alpicola<br />
1. Stem without central strand, leaf cells to 14 µm or less, quadrate papillose or elongate smooth cells on the adaxial<br />
surface <strong>of</strong> the costa; plants typically larger than 1.5 cm, plants on limestone pavements or <strong>of</strong> general distribution<br />
throughout northern North America . . .. 2
26<br />
2. Leaf cells generally 14 µm; elongate, smooth ste<strong>re</strong>id cells exposed on the adaxial surface <strong>of</strong> the costa<br />
throughout the leaf length in all cauline leaves; plants <strong>of</strong> limestone pavements in the G<strong>re</strong>at Lakes <strong>re</strong>gion . . .<br />
. Tortella rigens<br />
2. Leaf cells to 12 µm or less, adaxial surface <strong>of</strong> the costa partially cove<strong>re</strong>d by quadrate, papillose<br />
epidermal cells in stem leaves, plants <strong>of</strong> North Temperate, Bo<strong>re</strong>al and Arctic distribution . . . . 3<br />
3. Leaves e<strong>re</strong>ct and stiff, lamina intact, leaf developing a morphologically distinct deciduous<br />
apical propagulum, leaves in section <strong>re</strong>gularly bistratose in the apical portion . . . . Tortella<br />
fragilis<br />
3. Leaves generally crisped, lamina tatte<strong>re</strong>d, leaf not developing an apical propagulum, me<strong>re</strong>ly<br />
disintegrating in pieces, leaves in section ir<strong>re</strong>gularly bistratose in patches . . . . Tortella tortuosa<br />
var. fragilifolia<br />
Specimens examined, with annotations:<br />
Alta: 6000 ft. (1820 m) in tundra, Crum & Sch<strong>of</strong>ield<br />
5742 (MICH, UBC) ( with ext<strong>re</strong>mely long,<br />
slender, tatte<strong>re</strong>d leaves to 7 mm).<br />
Alta: rather dry boulders near Athabasca Falls, 20 mi. S.<br />
<strong>of</strong> Jasper, 4100 ft. (1241 m), June 25, 1955, H.<br />
Crum 3700 (MICH); tundra, slopes <strong>of</strong> Forum<br />
Peak, above Cameron Lake, ca. 6000 ft. (2000<br />
m), Waterton Lakes National Park, July 30,<br />
1955, H. Crum & W. B. Sch<strong>of</strong>ield 5742<br />
(MICH).<br />
B.C.: outcrop c<strong>re</strong>vices Mt. Liumchen-Church Mt a<strong>re</strong>a,<br />
49°02'N, 121°50'W, Sch<strong>of</strong>ield 63200 (UBC).<br />
(The only thing to associate this specimen with<br />
the variety, other than general aspect, was the<br />
distal leaf cross section which displayed a<br />
brightly chlorophyllose adaxial epidermis<br />
covering the adaxial ste<strong>re</strong>id layer, this latter<br />
vanishing toward the apex, leaving the<br />
quadrate cells intact. The<strong>re</strong> was no central<br />
strand and the diameter <strong>of</strong> the stem in section<br />
was small).<br />
B.C.: Sn. Cariboo Mtns 52°N, 120°W., moist hummock<br />
on river sho<strong>re</strong>, distal Tsuga zone, Leena &<br />
Teuvo Ahti 13730 (UBC). (Identified by the<br />
leaf cross section: all leaves intact.)<br />
Alaska: southeast; above t<strong>re</strong>e line (2200–3160') on<br />
Harbor Mtn. above Sitka, Baran<strong>of</strong> I., mostly<br />
slopes <strong>of</strong> exposed rocks in heathers, shaded<br />
rock angle, Aug. 4, 1968, I. A. Worley & F. M.<br />
Boas 10066 (UBC).<br />
Calif.: Siskiyou Co., moist, rather shaded rock outcrop<br />
in seepage, in open alder, incense cedar and<br />
white fir fo<strong>re</strong>st on south slopes <strong>of</strong> Red Butte<br />
near Cook & G<strong>re</strong>en Pass, 6500 ft. (2170 m), 28<br />
Sept., 1977, D. H. Norris 50265 (UBC). (The<br />
specimen in leaf cross section had the quadrate<br />
adaxial epidermis intact, the adaxial ste<strong>re</strong>id<br />
disappea<strong>re</strong>d and some <strong>of</strong> the cells we<strong>re</strong> with<br />
bistratose patches, no stem central strand.)<br />
Wash.: North Cascades, Rainy Pass a<strong>re</strong>a, Lewis Glacier<br />
and Lake, subalpine meadows, seepy slope<br />
above lake, under water in temp. snowmelt<br />
st<strong>re</strong>am in subalpine, 48°N 121'W, June 29,<br />
1982, J. Spence 1077 (UBC).<br />
A form <strong>of</strong> variation seen in only one specimen<br />
was the p<strong>re</strong>sence <strong>of</strong> quadrate, chlorophyllose papillose<br />
cells on the back <strong>of</strong> the costa in the leaf apex (Alberta,<br />
Crum 3512 UBC) which was acicular and nearly<br />
cylindric. The<strong>re</strong> is a variety <strong>of</strong> Tortella nitida in Europe<br />
(var. irrigatum (Winter) Zand., see below) that has this<br />
featu<strong>re</strong>, but the specimen cited he<strong>re</strong> is the only occasion<br />
in T. tortuosa s.l. noticed in the p<strong>re</strong>sent study <strong>of</strong> this<br />
featu<strong>re</strong>.<br />
5. TORTELLA FRAGILIS Plate 6<br />
Tortella fragilis (Drumm.) Limpr., Laubm. Deutschl. 1:<br />
606. 1888.<br />
Didymodon fragile [sic] Drumm., Musci Amer.<br />
(Rocky Mts.) 127. 1828.<br />
Trichostomum fragile (Drumm.) C. Müll., Syn.<br />
Musc. 1: 586. 1849.<br />
Barbula fragilis (Drumm.) BSG, Bryol. Eur. 6:<br />
157. 1855 (fasc. 62–65 Mon. Suppl. 4:<br />
1.), hom. illeg.<br />
Tortula drummondii Mitt., Jour. Linn. Soc.<br />
London Bot. 1(Suppl.): 27. 1859.<br />
Mollia fragilis (Hook. & Wils.) Lindb., Musci<br />
Scand. 21. 1879.<br />
Plants coarse, rigid, dark g<strong>re</strong>en to yellowish or<br />
blackish-brown in dense tufts or deep sods, elongate.<br />
Stems (0.5–)1–5 cm high, leaves distantly disposed<br />
along the stem with shining leaf bases usually appa<strong>re</strong>nt,<br />
central strand absent, densely and visibly radiculose the<br />
enti<strong>re</strong> stem length, ra<strong>re</strong>ly somewhat tomentose when<br />
very small. Stem leaves firm, coarse, rigid, uniform in<br />
size and shape along the stem, not app<strong>re</strong>ciably larger at<br />
the stem apex, lowermost leaves mostly without leaf<br />
tips, leaves typically fragile only at base <strong>of</strong> deciduous<br />
apical subula, stiffly e<strong>re</strong>ct-app<strong>re</strong>ssed, incurved (or stemapical<br />
leaves somewhat twisted around the stem when<br />
dry); e<strong>re</strong>ct and weakly sp<strong>re</strong>ading when moist, narrowly<br />
lanceolate to linear, narrowing gradually above the<br />
proximal <strong>re</strong>gion until gradually or quickly contracting<br />
into a narrower propaguloid <strong>re</strong>gion up to 1/2 the distal<br />
leaf length; broadly to narrowly concave, keeled toward<br />
the apex in non-propaguloid leaves, 4–6 mm long; base<br />
broadly oblong; margins plane to e<strong>re</strong>ct, not to<br />
somewhat undulate; apex narrowly acute, those <strong>of</strong> nonmodified<br />
leaves shallowly channeled to subnaviculate,<br />
not cucullate, those <strong>of</strong> modified leaves long-subulate,<br />
fragile, the subula obtusely thickened and multi-stratose<br />
distally and <strong>of</strong>ten broken <strong>of</strong>f, youngest leaves arising
from the stem apex fully propagulose and subulate;<br />
costa short-excur<strong>re</strong>nt as a smooth or weakly denticulate<br />
mucro <strong>of</strong> 1–5 rhomboidal cells, in propaguloid leaves,<br />
internal cells in section appearing undiffe<strong>re</strong>ntiated in the<br />
subula; adaxial surface cove<strong>re</strong>d by quadrate to short<strong>re</strong>ctangular,<br />
papillose laminal cells throughout the leaf<br />
except in the propaguloid leaf portion whe<strong>re</strong> a narrow<br />
medial groove is cove<strong>re</strong>d by elongate (8:1) smooth<br />
cells; cross section lunate and broad, adaxial epidermal<br />
cells may be interrupted in the center, exposing the<br />
adaxial ste<strong>re</strong>id layer by about two cells in width, adaxial<br />
and abaxial ste<strong>re</strong>id bands p<strong>re</strong>sent, guide cells p<strong>re</strong>sent in<br />
one layer, in propaguloid leaves appearing<br />
undiffe<strong>re</strong>ntiated in the subula; proximal laminal cells<br />
rather abruptly diffe<strong>re</strong>ntiated from distal cells, usually<br />
lacking a zone <strong>of</strong> cells intermediate in color, cell size,<br />
and papillosity, occasionally with an intermediate zone<br />
<strong>of</strong> thick-walled somewhat porose cells, yellow-hyaline,<br />
elongate, firm to laxly thin-walled, smooth; marginal<br />
angle <strong>of</strong> diffe<strong>re</strong>ntiated proximal cells steep, with a<br />
narrow line <strong>of</strong> firm to thin-walled cells extending a<br />
short way up the lamina or to mid-leaf; distal laminal<br />
cells f<strong>re</strong>quently bistratose on one or both laminae beside<br />
the costa, or equally extending toward the margins in<br />
various deg<strong>re</strong>es, and becoming completely bistratose<br />
and ultimately undiffe<strong>re</strong>ntiated in the, deciduous leaf<br />
tips, rounded-quadrate or hexagonal, (9–)10–12(–13)<br />
µm wide, strongly papillose, a<strong>re</strong>olation mo<strong>re</strong> or less<br />
distinct; marginal cells in median leaf <strong>re</strong>gion<br />
undiffe<strong>re</strong>ntiated, papillose-c<strong>re</strong>nulate, along the distal<br />
median margin and into the subula diffe<strong>re</strong>ntiated as one<br />
or two rows <strong>of</strong> smooth, thick-walled, short-<strong>re</strong>ctangular,<br />
(4–3:1), epapillose, yellowish cells leading into the<br />
subulate <strong>re</strong>gion and extending to the apex distinctly<br />
visible in at least some leaves, sometimes p<strong>re</strong>sent only<br />
in young leaves on matu<strong>re</strong> stems. Asexual<br />
<strong>re</strong>production: modification for asexual <strong>re</strong>production by<br />
deciduous, subulate, rigid, smooth-sided, distally<br />
thickened apices <strong>of</strong> all leaves. Sexual condition<br />
dioicous, seldom fruiting. Perigonia not seen.<br />
Perichaetial leaves setaceous, fragile, with propaguloid<br />
modifications as in stem leaves. Seta <strong>re</strong>d-orange below,<br />
paler above, 1.5–2 cm long, occasionally two per<br />
perichaetium. Capsule 1.8–3 mm long; annulus none or<br />
<strong>of</strong> 1–2 rows <strong>of</strong> weakly vesiculose cells, operculum ca.<br />
1.5 mm long; peristome teeth long, spirally wound<br />
together, twisted 1, 2 or 3 times. Calyptra cucullate.<br />
Spo<strong>re</strong>s 8–10 µm, nearly smooth.<br />
Spo<strong>re</strong>s matu<strong>re</strong> in summer (June).<br />
A common moss <strong>of</strong> northern <strong>re</strong>gions on<br />
various substrates probably desiccated at least during<br />
some <strong>of</strong> the year, on acid or calca<strong>re</strong>ous rock, in seepage,<br />
and in c<strong>re</strong>vices and ledges <strong>of</strong> cliffs in maritime<br />
situations, dry prairies, on logs or peaty humus in<br />
springs, fens, Thuja swamps, on the open sands <strong>of</strong> lake<br />
sho<strong>re</strong>s, in the north or in mountains, in tundra, alpine<br />
and willow bogs, frost boils, margins <strong>of</strong> solifluction<br />
lobes, snow patch margins; elevation sea level to 3600<br />
m; G<strong>re</strong>enland; Alta, B.C., Lab., Man., N.B., Nfld.,<br />
N.W.T., N.S., Ont., Que., Yukon; Alaska, Colo., Iowa,<br />
27<br />
Mich., Minn., Mont., [N. Car.], N.J., N.Y., N.Dak.,<br />
O<strong>re</strong>g., S.Dak., Tenn., Vt., Wash., Wyo.; Europe, Asia,<br />
Africa, Australasia in New Zealand; Antarctica;<br />
"<strong>re</strong>aching Nevada in the western mountains. Iceland;<br />
Svalbard, widely distributed in the mountains <strong>of</strong><br />
Europe; through the Himalayan chain to China; across<br />
northern and Arctic Asiatic USSR; Japan" (Stee<strong>re</strong><br />
1978).<br />
Herbaria examined: BUF, CANM, COLO,<br />
DUKE, FLAS, MICH, MO, UBC.<br />
A North Temperate, bo<strong>re</strong>al and Arctic species<br />
whose southern range hovers around the Canadian-<br />
United States border, but extending south in the<br />
mountains.<br />
Tortella fragilis is characteristic <strong>of</strong> the high<br />
Arctic. It is the only <strong>re</strong>p<strong>re</strong>sentative <strong>of</strong> the genus in<br />
Arctic Europe (Arctic Scandinavia and Spitsbergen)<br />
according to Crundwell and Nyholm (1964). In Arctic<br />
Asia and North America it is joined by Tortella tortuosa<br />
var. arctica, and by var. tortuosa throughout its range.<br />
Numerous collections from the Northwest Territories<br />
we<strong>re</strong> found mixed with T. inclinata var. densa.<br />
In Europe, the occur<strong>re</strong>nce <strong>of</strong> Tortella fragilis,<br />
rather like T. tortuosa, is concentrated in the Alps and<br />
their foothills (Braunmiller et al. 1971). Stations in the<br />
north, such as southern Sweden, may be the <strong>re</strong>sult <strong>of</strong><br />
dispersal by apical fragmentation. Both Braunmiller et<br />
al. (1971) and Düll and Meinunger (1989) map the<br />
concentration <strong>of</strong> this species in Germany in the ext<strong>re</strong>me<br />
south in the highlands near the Swiss-Austrian border<br />
and with few stations elswhe<strong>re</strong> in that country.<br />
Tortella fragilis has a bipolar distribution.<br />
Specimens examined from the Southern Hemisphe<strong>re</strong><br />
(New Zealand, Tierra del Fuego, South Africa) show the<br />
same range <strong>of</strong> statu<strong>re</strong> and variation as North American<br />
plants <strong>of</strong> this species. Hyvönen (1991) <strong>re</strong>cently<br />
described the species from southern South America in<br />
Tierra del Fuego from sea level to 610 m on "ba<strong>re</strong> soil<br />
and schistose gravel." The species has additionally been<br />
<strong>re</strong>ported in the Southern Hemisphe<strong>re</strong>: New Zealand<br />
(Fife 1984; Vitt 1974) and South Africa (Magill 1981),<br />
(South African specimen J van Rooy 3127BB, BUF). I<br />
have also seen specimens <strong>of</strong> Tortella fragilis at BUF<br />
collected from Antarctica (R. I. Lewis-Smith 7674B;<br />
9277D).<br />
Hyvönen (1991) discussed specimens from the<br />
Antarctic, originally described as Sarconeurum<br />
tortelloides S.W.G<strong>re</strong>ene, as T. fragilis. However, my<br />
examination <strong>of</strong> this material proved it to be Tortella<br />
alpicola and not T. fragilis. Tortella alpicola always has<br />
a stem central strand. This character is absent in T.<br />
fragilis. Tortella fragilis has been <strong>re</strong>ported for Hawaii<br />
(as var. tortelloides (S. W. G<strong>re</strong>ene) Zand. & Hoe<br />
(Zander & Hoe 1979). The Hawaiian material is also T.<br />
alpicola, and so T. fragilis is excluded from that Pacific<br />
island. The only species <strong>of</strong> Tortella occurring the<strong>re</strong>,<br />
other than T. alpicola, is T. humilis (Hoe 1974).<br />
In northern <strong>re</strong>gions, Tortella fragilis is<br />
f<strong>re</strong>quently found with Distichium capillaceum (Hedw.)<br />
B.S.G, which also has long, subulate leaves, but which
has no proximal cells diffe<strong>re</strong>ntiated higher on the<br />
margins, with leaves distichous on the stem, and short<br />
peristome teeth that a<strong>re</strong> not elongated and twisted.<br />
The long, subulate, rigid, usually fragile leaves<br />
with propaguloid tips that a<strong>re</strong> not or only slightly<br />
contorted when dry a<strong>re</strong> distinctive <strong>of</strong> Tortella fragilis.<br />
In ambiguous cases, the bistratose cross section <strong>of</strong> the<br />
distal leaves is diagnostic, but usually all that is<br />
necessary is to demonstrate the smooth, elongate,<br />
thicker-walled cells along the leaf margin near the apex,<br />
a characteristic trait illustrated by Abramova et al.<br />
(1961: 296). That such a border is somewhat discernible<br />
in the deciduous apices <strong>of</strong> some leaves <strong>of</strong> Tortella<br />
rigens is one indication <strong>of</strong> that species possibly sharing<br />
genes with T. fragilis (see discussion under T. rigens).<br />
It is possible that the thick-walled marginal<br />
cells which occur in the distal leaf <strong>re</strong>gions and in the<br />
propagules, rather than continuously along the margins<br />
such as might be expected from simply an extension <strong>of</strong><br />
the proximal marginal cells higher up the leaf,<br />
contributes to the efficiency by which the plant<br />
maintains the structural integrity <strong>of</strong> the propagule when<br />
it detaches. Regions <strong>of</strong> the leaf that have no elongate<br />
marginal cells appear to have no particular diaspo<strong>re</strong><br />
function, and rigidity may not be necessary. In fact, the<br />
absence <strong>of</strong> strong marginal cells contributes to the<br />
detachability <strong>of</strong> the rigid diaspo<strong>re</strong>, hence the middle<br />
third <strong>of</strong> the leaves has neither proximal nor distal-leaf<br />
marginal cells. No specimens <strong>of</strong> Tortella fragilis we<strong>re</strong><br />
found without at least some leaves displaying<br />
diffe<strong>re</strong>ntiated distal marginal cells.<br />
Note that some robust leaves <strong>of</strong> Tortella<br />
inclinata var. densa have elongate, smooth-walled<br />
laminal cells, but mo<strong>re</strong> f<strong>re</strong>quently in the proximal part<br />
<strong>of</strong> the leaf and without evident cor<strong>re</strong>lation with a<br />
diaspo<strong>re</strong>.<br />
In Tortella fragilis the leaf cell size is not<br />
necessarily uniform throughout the leaf: while the<br />
quadrate cell size may be 7–10 µm in the medial <strong>re</strong>gion<br />
<strong>of</strong> the lamina, it may <strong>re</strong>ach 14 µm in the deciduous<br />
apical leaf <strong>re</strong>gion.<br />
A g<strong>re</strong>ater range <strong>of</strong> variability in the leaves <strong>of</strong><br />
Tortella fragilis was seen than is usually described: the<br />
leaves may be stiff and me<strong>re</strong>ly arcuate in some plants,<br />
in others variously to strongly contorted-circinate, but<br />
not crisped. Such plants may be difficult to distinguish<br />
from Tortella tortuosa var. fragilifolia, which, however,<br />
has a fragile leaf lamina in addition to fragile leaf<br />
apices.<br />
In other collections the<strong>re</strong> is a distinctive<br />
dimorphism in the leaves, especially in innovating<br />
branches, with strongly crisped-contorted leaves without<br />
propaguloid subulae but instead short, denticulate sharp<br />
mucros subtending typical stiff, subulate-propaguloid<br />
leaves toward the shoot apex.<br />
Occasionally a specimen will occur that does<br />
not develop the deciduous leaf apices; the leaves a<strong>re</strong><br />
me<strong>re</strong>ly partially bistratose near the costa and hence<br />
identification is problematic (usually identified in<br />
herbarium specimens as Tortella tortuosa). The overall<br />
28<br />
rigidity <strong>of</strong> the leaves on the stem, wet or dry and the<br />
elongate cells on the leaf margins a<strong>re</strong>, however,<br />
definitive. Such plants, especially in mountain a<strong>re</strong>as in<br />
the United States and northern North America, ra<strong>re</strong>ly<br />
exhibit some leaves with rather large cells (to 14 µm) in<br />
the apical portion <strong>of</strong> the leaves and have been identified<br />
as T. rigens (see discussion below).<br />
In Quebec, the species is <strong>of</strong>ten <strong>re</strong>p<strong>re</strong>sented by<br />
tiny, depauperate plants with short, ovate-lanceolate<br />
leaves, yet with the distinctive distal border. In the most<br />
robust stems <strong>of</strong> these plants the cylindrical leaf-apical<br />
propagulum emerging from the stem tip in the youngest<br />
leaves helps identification (see illustration). As one<br />
might expect, leaves from these specimens a<strong>re</strong> only<br />
partially bistratose beside the costa. Specimens such as<br />
these a<strong>re</strong> usually identified in herbarium specimens as<br />
Tortella tortuosa.<br />
In specimens <strong>of</strong> Tortella fragilis whe<strong>re</strong> the<br />
propaguloid apices a<strong>re</strong> not very well developed, the<br />
leaves tend to be twisted instead <strong>of</strong> stiff. One specimen<br />
(Quebec, Macoun, Aug. 26, 1883, CANM) had long,<br />
subulate leaves with distal marginal borders but with the<br />
propagula <strong>re</strong>stricted to only some leaves and then only<br />
near the ext<strong>re</strong>me leaf tips, exp<strong>re</strong>ssed as a short, round<br />
section below the mucro, hence generally fewer leaf<br />
apices we<strong>re</strong> missing. Occasionally (Alberta, Crum &<br />
Sch<strong>of</strong>ield 4609, UBC) the<strong>re</strong> is no propagulum<br />
development at all and one must be guided by the clear,<br />
smooth-celled (rather than papillose-c<strong>re</strong>nulated) distal<br />
margins, the bistratose a<strong>re</strong>a near the costa in section,<br />
and the e<strong>re</strong>ct, non-undulate leaves.<br />
Younger leaves and the leaves <strong>of</strong> young plants<br />
<strong>of</strong> Tortella fragilis may be tipped with a multicellular (5<br />
or 6 cell) mucro much like that <strong>of</strong> T. tortuosa, but the<br />
bistratose margins and the elongate clear cells on the<br />
leaf margin (these cells <strong>of</strong>ten absent in matu<strong>re</strong> leaves) in<br />
addition to fragile, propaguloid leaves a<strong>re</strong> characteristic.<br />
The leaf apices <strong>of</strong> T. tortuosa have very long mucros,<br />
mostly mo<strong>re</strong> than 5 cells in length.<br />
Quadrate, papillose epidermal cells across the<br />
adaxial portion <strong>of</strong> the costa occur throughout the leaf <strong>of</strong><br />
Tortella fragilis except in the proximal cell <strong>re</strong>gion and<br />
in the propaguloid-setaceous part <strong>of</strong> the leaf whe<strong>re</strong> the<br />
costa is <strong>of</strong>ten exposed in a continuous groove <strong>of</strong><br />
elongate cells. This character is useful in distinguishing<br />
the species from T. rigens, which has a continuous band<br />
<strong>of</strong> smooth, elongate cells on the adaxial surface <strong>of</strong> the<br />
costa throughout the length <strong>of</strong> the leaf.<br />
The abaxial dorsal ste<strong>re</strong>id band is without<br />
quadrate, papillose cells throughout the length <strong>of</strong> the<br />
leaf. Transverse sections throughout the subulate<br />
propagulum in the distal leaf portion <strong>re</strong>veals a <strong>re</strong>duction<br />
in the the diffe<strong>re</strong>nt layers <strong>of</strong> the leaf as well as their<br />
surface characteristics, and yet, excepting for the guide<br />
cell layer, they can still be somewhat diffe<strong>re</strong>ntiated in<br />
various deg<strong>re</strong>es by the smoothness <strong>of</strong> the surficial cell<br />
walls: the marginal cells can be identified by their<br />
smooth marginal surface, the ste<strong>re</strong>id cells, whether <strong>of</strong><br />
the abaxial or adaxial band, can also be identified by<br />
their smoothness in at least one or two cells. The
laminal cells can be identified by the papillosity <strong>of</strong> the<br />
cell surfaces.<br />
In Tortella alpicola, the lamina is never<br />
bistratose except juxtacostally. The lamina is abruptly<br />
rather than gradually contracted into a mo<strong>re</strong> <strong>re</strong>adilly<br />
deciduous propagulum. While the lamina <strong>of</strong> T. alpicola<br />
is unistratose, only the costa becomes undiffe<strong>re</strong>ntiated<br />
in section, quadrate papillose cells clothe the dorsal<br />
surface <strong>of</strong> the costa in the apex <strong>of</strong> leaves at the distal<br />
end <strong>of</strong> the stem. Quadrate papillose cells at the back <strong>of</strong><br />
the costa at the leaf tip <strong>of</strong> plants <strong>of</strong> T. nitida have been<br />
distinguished by a varietal name (var. irrigata (Winter)<br />
Zand., see discussion below).<br />
Tortella alpicola is further distinguished by the<br />
stem central strand, large leaf cells, absence <strong>of</strong><br />
tomentum and sterile stems (see discussion above).<br />
North American specimens identified as<br />
Tortella rigens by the late F. J. Hermann we<strong>re</strong><br />
somewhat odd exp<strong>re</strong>ssions <strong>of</strong> T. fragilis in wet tundra<br />
(see discussion under T. rigens). Specimens <strong>of</strong> other<br />
Tortella species with stiff, unbroken, subulate leaves at<br />
the stem tip <strong>of</strong>ten <strong>re</strong>semble T. fragilis. Usually these a<strong>re</strong><br />
perichaetial leaves at the stem tips <strong>of</strong> T. tortuosa, T.<br />
inclinata var. inclinata or T. alpicola. Perichaetial<br />
leaves <strong>of</strong> these species <strong>of</strong>ten show diffe<strong>re</strong>ntiated<br />
elongate smooth cells on the margin as in T. fragilis, but<br />
they a<strong>re</strong> not modified into propagula at the leaf tips, nor<br />
a<strong>re</strong> they bistratose.<br />
A <strong>re</strong>duced form <strong>of</strong> Tortella fragilis seen from<br />
New Zealand approximated T. alpicola. However,<br />
elongate, smooth marginal cells on propaguloid leaves<br />
could be demonstrated on a few <strong>of</strong> the leaves, at least<br />
some <strong>of</strong> the stems we<strong>re</strong> rufous-tomentose, and the<br />
proximal cells we<strong>re</strong> yellow (not hyaline). When stems<br />
a<strong>re</strong> 1 cm or less in length, the su<strong>re</strong>st way to diffe<strong>re</strong>ntiate<br />
T. alpicola is to examine the primordial leaves at the top<br />
<strong>of</strong> the stem: in T. alpicola they will be rough with<br />
papillae, with <strong>re</strong>gular 'bar<strong>re</strong>l-shaped' caducous<br />
segments; in T. fragilis they will have straight, clean<br />
edges borde<strong>re</strong>d by elongate, smooth cells, and will<br />
comprise a single unit.<br />
Specimens <strong>of</strong> Tortella rigens from the Baltic<br />
<strong>re</strong>gion, whe<strong>re</strong> it was hitherto been conside<strong>re</strong>d endemic,<br />
we<strong>re</strong> examined and we<strong>re</strong> found to sha<strong>re</strong> many <strong>of</strong> the<br />
characteristics <strong>of</strong> T. fragilis, except that the leaves did<br />
not fully develop the distinctive subulate propaguloid<br />
leaf apices. Although much mo<strong>re</strong> contorted than typical<br />
T. fragilis, the leaves <strong>of</strong> T. rigens a<strong>re</strong>, as the epithet<br />
suggests, mo<strong>re</strong> rigid than other species in the genus.<br />
Specimens <strong>of</strong> T. rigens examined with large leaves also<br />
had a border <strong>of</strong> elongated, thicker-walled, and smoother<br />
marginal cells in the distal third <strong>of</strong> the leaf. Dissection<br />
<strong>of</strong> the larger, mo<strong>re</strong> developed leaves in the collections<br />
<strong>re</strong>vealed them to have a cross section similar to that <strong>of</strong><br />
T. fragilis: bistratose juxtacostally, but the distal laminal<br />
cells we<strong>re</strong> much larger and young leaves at the stem tips<br />
showed immatu<strong>re</strong> leaves without propaguloid<br />
modifications. Although T. fragilis may develop stems<br />
that a<strong>re</strong> to one centimeter tall without losing its<br />
principle characteristics, small T. rigens plants appear to<br />
29<br />
lose most <strong>of</strong> their T. fragilis-like featu<strong>re</strong>s and<br />
<strong>re</strong>semble mo<strong>re</strong> and mo<strong>re</strong> a diffe<strong>re</strong>nt kind <strong>of</strong> plant<br />
altogether. However, even in populations <strong>of</strong> very small<br />
plants <strong>of</strong> T. rigens, larger leaves may be extracted that<br />
show the somewhat elongate distal marginal cells that<br />
indicate its affinity to T. fragilis. These leaves, on<br />
sectioning, will be bistratose next to the costa,<br />
sometimes imperfectly so (e.g. on only one lamina).<br />
Variation in the leaf-shape is extensive among diffe<strong>re</strong>nt<br />
stems in the same collection, such that leaves that<br />
appear consistent with the description a<strong>re</strong> found, but<br />
the<strong>re</strong> a<strong>re</strong> always those stems that bear T. fragilis-like<br />
modifications, such as the abrupt acumination or<br />
constriction at the base <strong>of</strong> a subuloid distal leaf <strong>re</strong>gion<br />
(to 1/3 the leaf length), that is similar to T. fragilis.<br />
These plants a<strong>re</strong> strikingly diffe<strong>re</strong>nt in low<br />
magnification: their true affinities a<strong>re</strong> most appa<strong>re</strong>nt on<br />
examination <strong>of</strong> the cross-section <strong>of</strong> the leaf: T. fragilis<br />
will be strongly bistratose with quadrate, papillose cells<br />
on the adaxial surface <strong>of</strong> the costa in the median-leaf<br />
<strong>re</strong>gion, T. rigens only juxtacostally bistratose with a<br />
groove <strong>of</strong> elongate, smooth cells on the adaxial surface<br />
<strong>of</strong> the costa throughout.<br />
The occasional specimen <strong>of</strong> Tortella fragilis in<br />
North America has been ascribed to T. nitida perhaps<br />
when all or most <strong>of</strong> the leaf apices <strong>of</strong> a specimen a<strong>re</strong><br />
absent (e.g. Alberta, C. D. Bird 5514, CANM, with a<br />
query). Tortella nitida has a strong stem central strand,<br />
poorly diffe<strong>re</strong>ntiated proximal cells except along the<br />
proximal margins <strong>of</strong> the leaf, its leaf is fragile<br />
throughout the lamina, rather than with a deciduous leaf<br />
apex, nor in section is the lamina anywhe<strong>re</strong> bistratose. It<br />
is excluded from North America (see discussions above<br />
under T. tortuosa var. fragilifolia, and below under T.<br />
nitida.)<br />
6. TORTELLA INCLINATA Plates 8–9<br />
Tortella inclinata (R. Hedw.) Limpr., Laubm. Deutschl.<br />
1: 602. 1888.<br />
Barbula inclinata (R. Hedw.) Schwaegr., Spec.<br />
Musc. Suppl. 1(1): 131. 1811.<br />
Tortula inclinata R. Hedw., Beitr. Naturk. 1:<br />
123. 1805.<br />
Barbula fragilis ssp. inclinata (R. Hedw.)<br />
Boul., Muscin. France 422. 1884,<br />
nom. illeg. prior. ut spec.<br />
Mollia inclinata (R. Hedw.) Lindb. in<br />
Braithw., Brit. Moss Fl. 1: 251. 1887.<br />
Barbula inclinatula C. M. & Kindb. in Macoun<br />
& Kindb., Cat. Canad. Pl. 6: 50. 1892.<br />
Trichostomum inclinatum (R. Hedw.) Dix.,<br />
Stud. Handb. Brit. Moss. 219. 1896.<br />
Tortella inclinatula (C. Müll. & Kindb. in<br />
Mac. & Kindb.) Broth., Engler &<br />
Prantl, Musci ed.1. 397. 1909.<br />
Plants in dense, low tufts or turves, dull yellow-g<strong>re</strong>en to<br />
yellowish brown above, brown below, elongate, not<br />
rosulate. Stems 0.5–1(–1.5) cm high, central strand
absent; few-branched, stem sparsely rufous radiculosetomentose<br />
at the base, essentially without tomentum<br />
above. Stem leaves somewhat s<strong>of</strong>t or lax, loosely to<br />
mo<strong>re</strong> closely foliose, variably gradually somewhat<br />
larger and mo<strong>re</strong> crowded toward the stem tips or the<br />
<strong>re</strong>verse with the leaves somewhat larger below than<br />
above, loosely and ir<strong>re</strong>gularly curled to crisped when<br />
dry, e<strong>re</strong>ct-sp<strong>re</strong>ading to sp<strong>re</strong>ading when moist, oblonglanceolate,<br />
to lanceolate, sides generally parallel and<br />
scarcely tape<strong>re</strong>d from the base, typically strongly<br />
keeled-concave or broadly channeled across the leaf<br />
adaxially, (1–)1.5–2 mm long, not undulate; base not<br />
diffe<strong>re</strong>ntiated or somewhat broader, elliptical; margins<br />
plane to e<strong>re</strong>ct, broadly incurved above, not undulate;<br />
apex typically cucullate, occasionally fistulose, obtuse<br />
to acute, occasionally abruptly narrowed and concaveacuminate;<br />
costa short-excur<strong>re</strong>nt by 1–3 cells, cells <strong>of</strong><br />
the adaxial surface cells enti<strong>re</strong>ly smooth and narrowly<br />
elongated, 8:1, throughout, adaxial epidermis absent,<br />
adaxial and abaxial ste<strong>re</strong>id bands p<strong>re</strong>sent, guide cells<br />
p<strong>re</strong>sent in one row, in cross section nearly circular,<br />
without bistratose a<strong>re</strong>as at junctu<strong>re</strong> with lamina;<br />
occasionally abaxial surface roughened by projecting<br />
distal cell ends, these mo<strong>re</strong> dense at the leaf apex;<br />
proximal laminal cells abruptly diffe<strong>re</strong>ntiated from<br />
30<br />
distal cells in color, cell size, cell wall thickness and<br />
papillosity, proximal pale yellow, transpa<strong>re</strong>nt, elongate,<br />
laxly very thin-walled and fragile, smooth; V-shaped<br />
marginal angle steep; marginal cells undiffe<strong>re</strong>ntiated,<br />
sharply c<strong>re</strong>nulate-papillose; distal laminal cells densely<br />
and sharply papillose, quadrate, 10–12 µm wide.<br />
Asexual <strong>re</strong>production: modifications for asexual<br />
<strong>re</strong>production none. Sexual condition: dioicous, seldom<br />
fruiting. Perigonia not seen. Perichaetial leaves with<br />
unfertilized archegonia hidden in the circumperichaetial<br />
stem leaves; perichaetial leaves <strong>of</strong> fertilized archegonia<br />
conspicuously diffe<strong>re</strong>ntiated, elongate, 2–5.5 mm long,<br />
e<strong>re</strong>ct from a broad, long and hyaline sheathing<br />
sometimes inflated base, not or somewhat curled at the<br />
tips when dry, rising above the crispate stem leaves<br />
below, narrowly lance-subulate with a long excur<strong>re</strong>nt<br />
costa, in some leaves with an interrupted border <strong>of</strong><br />
elongate, thick-walled smooth cells in the distal portion<br />
<strong>of</strong> the leaf. Seta orange, paler above, 1.5–2.7 cm long.<br />
Capsule 1.5–2 mm long, yellow-orange, <strong>re</strong>d at the<br />
mouth; annular cells not vesiculose; operculum 1–2 mm<br />
long; peristome teeth long (to 0.7 mm), spirally wound<br />
mo<strong>re</strong> than once. Calyptra cucullate. Spo<strong>re</strong>s 9–12 µm,<br />
appearing smooth or with minute papillae.<br />
KEY TO THE VARIETIES OF TORTELLA INCLINATA<br />
1. Stems short, to 1 cm, not to few-branched, tomentum usually conspicuous; leaf cross section with adaxial and<br />
abaxial superficial walls the same width as the cross-walls; papillae not elevated, leaf cells 10–12 µm, stems yellow<br />
or g<strong>re</strong>en, rather pale, brown below, yellow in KOH, leaves ir<strong>re</strong>gularly twisted and incurved when dry; majority <strong>of</strong><br />
leaf apices obtuse, strongly cucullate, mucros <strong>of</strong> 1–3 cells; in low sandy alluvium <strong>of</strong> beaches and st<strong>re</strong>ams . . . . 6a.<br />
Tortella inclinata var. inclinata<br />
1. Stems tall, to 2 cm, many-branched, tomentum hidden in leaf axils; leaf cross section with thick abaxial and<br />
adaxial superficial walls, but thin cross-walls; papillae appearing pedestaled on thick walls, leaf cells 7–10 µm,<br />
stems dull and <strong>of</strong>ten strongly orange-g<strong>re</strong>en, orange, or dull g<strong>re</strong>en above and brownish-black below, orange in KOH;<br />
leaves when dry somewhat uniformly twisted on the stem (funaliform), e<strong>re</strong>ct below; leaf apices cucullate, acute, to<br />
narrowly acuminate, mucros <strong>of</strong> 5–7 cells; in rock c<strong>re</strong>vices, hillsides and upland alluvium . . . . 6b. Tortella inclinata<br />
var. densa<br />
6a. TORTELLA INCLINATA VAR. INCLINATA<br />
Plate 8<br />
Leaves yellow-g<strong>re</strong>en, incurved and ir<strong>re</strong>gularly curled<br />
when dry, appearing s<strong>of</strong>t or lax; apices generally<br />
cucullate, distal laminal cells to 12 µm, not obscu<strong>re</strong>; cell<br />
walls uniformly medium, thin-walled, with dense,<br />
unpedestaled, rather high, solid papillae in sharp <strong>re</strong>lief.<br />
The variety is known to fruit in Alberta and<br />
British Columbia.<br />
This plant is associated with exposed<br />
calca<strong>re</strong>ous silt, sand or other loosely consolidated<br />
substrates whe<strong>re</strong> it functions as a pioneer species. It<br />
f<strong>re</strong>quently grows near bodies <strong>of</strong> inland f<strong>re</strong>sh water,<br />
gravel bars, among pebbles on river banks, mud flats,<br />
sand dunes on the G<strong>re</strong>at Lakes. It also is found in gravel<br />
pits near bogs and sandy clearings in mixed deciduous<br />
woods or spruce-pine groves, and highway ditches;<br />
elevation 200–1830 m; Alta., B.C., N.W.T., Ont., Que.,<br />
Yukon; Alaska, Iowa, Mich., Minn., Mont., Ohio;<br />
<strong>re</strong>ported from South America, Europe, Asia, Africa,<br />
Australia. "A widesp<strong>re</strong>ad species in Eurasia" (Stee<strong>re</strong><br />
1978).<br />
Spo<strong>re</strong>s matu<strong>re</strong> in spring (late May).<br />
Herbaria examined: BUF, CANM, COLO,<br />
DUKE, FLAS, MICH, MO, NY, UBC.<br />
In the course <strong>of</strong> the p<strong>re</strong>sent study, many<br />
specimens in North American herbaria <strong>of</strong> what has<br />
hitherto been determined to be Tortella inclinata have<br />
been <strong>re</strong>determined as two other taxa: T rigens and T.<br />
inclinata var. densa. The th<strong>re</strong>e taxa a<strong>re</strong> very similar in<br />
their tubulose and f<strong>re</strong>quently cucullate leaves, and the<br />
groove <strong>of</strong> elongate, smooth cells on the adaxial surface<br />
<strong>of</strong> the costa extending throughout the leaf. These th<strong>re</strong>e<br />
taxa a<strong>re</strong> rather substrate specific and this was a crucial<br />
element in their diffe<strong>re</strong>ntiation during this study. In<br />
North America, Tortella inclinata var. inclinata appears<br />
to be <strong>re</strong>stricted to "calca<strong>re</strong>ous silt, usually in the flood<br />
zone <strong>of</strong> st<strong>re</strong>ams" (Stee<strong>re</strong> (1978). The var. inclinata also<br />
enjoys larger sediments, such as the coarse sands along<br />
the G<strong>re</strong>at Lakes beaches and rivers. It characterizes<br />
lower a<strong>re</strong>as in flood zones than T. inclinata var. densa,
which also colonizes sandy soil, but in this case in the<br />
c<strong>re</strong>vices <strong>of</strong> rocks in hilly stations—perhaps in a<strong>re</strong>as<br />
flooded only when the waters a<strong>re</strong> very high.<br />
Stee<strong>re</strong> (1978) mentioned the occur<strong>re</strong>nce <strong>of</strong><br />
Tortella inclinata in Ontario based on a citation <strong>of</strong><br />
Williams (1968). Her habitat designation, "ba<strong>re</strong> open<br />
limestone flats in drier locations than Tortella tortuosa"<br />
suggests strongly that her specimen was T. rigens (see<br />
discussion below). Although in the alvar <strong>re</strong>gions <strong>of</strong><br />
southern Sweden, on the islands <strong>of</strong> Öland and Gotland,<br />
T. inclinata var. inclinata may grow on limestone, so far<br />
this habitat has not produced specimens in North<br />
America, hence it has not been found growing mixed<br />
with T. rigens. That T. inclinata is found growing in<br />
mixed populations with T. fragilis in Alberta (T.<br />
inclinata being fertile), and f<strong>re</strong>quently so in the Nahanni<br />
River a<strong>re</strong>a (based on numerous specimens at NY), is<br />
suggestive when one considers the possible hybrid<br />
natu<strong>re</strong> <strong>of</strong> T. rigens.<br />
Stee<strong>re</strong> (1978) discussed th<strong>re</strong>e disjunct a<strong>re</strong>as <strong>of</strong><br />
distribution in North America for Tortella inclinata, and<br />
these we<strong>re</strong> mapped and discussed by Miller (1976). The<br />
specimens mapped follow roughly the southern limits <strong>of</strong><br />
maximum Wisconsinan glaciation. Specimens seen by<br />
Miller we<strong>re</strong> examined in this study from CANM, MICH<br />
and NY, (but not FH or US), and some <strong>of</strong> them we<strong>re</strong><br />
<strong>re</strong>determined to be either T. rigens or T. inclinata var.<br />
densa. Fossil specimens <strong>of</strong> T. inclinata, noted by Miller<br />
(1976) from the Two C<strong>re</strong>eks Fo<strong>re</strong>st Bed peats <strong>of</strong><br />
Wisconsin, dated 12,000 to 11,850 years old, and from<br />
"sediments deposited during final ice withdrawal...and<br />
commencement <strong>of</strong> postglacial (Holocene) time about<br />
10,000 years ago" (Miller 1976) in northwestern New<br />
York State (Miller 1973) should be <strong>re</strong>-examined to see<br />
if they a<strong>re</strong> not T. inclinata var. densa. The northernmost<br />
station noted on Miller's (1976) map from Alaska in the<br />
Brooks Range, for example, is T. inclinata var. densa<br />
(see discussion under that taxon).<br />
Braunmiller et al. (1971) <strong>re</strong>port that Tortella<br />
inclinata var. inclinata is "ecologically rather sharply<br />
delimited on open, unprotected [unshade], strongly<br />
insolated and quickly desiccated calca<strong>re</strong>ous gravelly<br />
soil." They indicate it is a colonizer and dominant<br />
species in a pioneer-association: "zu der auch ande<strong>re</strong><br />
Tortella-Arten sowie die Flechten des Bunten<br />
Ardflechtenve<strong>re</strong>ins...gehö<strong>re</strong>n" (see Reimers 1951). It is<br />
not found on humus. It is found on calca<strong>re</strong>ous gravels <strong>of</strong><br />
rivers in the Alps and other calca<strong>re</strong>ous uplands. They<br />
state that a large part <strong>of</strong> the stations a<strong>re</strong> anthropogenic,<br />
colonizing gravel pits, excavations, ballust on railway<br />
embankments and similar substrates. They emphasize<br />
that like T. fragilis the center <strong>of</strong> distribution is in the<br />
Alps and its foothills. Many stations a<strong>re</strong> along the banks<br />
<strong>of</strong> the Danube and Rhein rivers. Stations in the German<br />
north a<strong>re</strong> suggested to be adventive. Inte<strong>re</strong>stingly, these<br />
authors a<strong>re</strong> uncertain about the altitudinal boundary <strong>of</strong><br />
the species in the Alps and they suggest that in higher<br />
altitudes, stations <strong>re</strong>ported as T. inclinata may be T.<br />
densa instead. The p<strong>re</strong>sent t<strong>re</strong>atment <strong>re</strong>solves these<br />
31<br />
issues by p<strong>re</strong>senting the taxa as a single variable<br />
species.<br />
Tortella inclinata var. inclinata has an<br />
enormous a<strong>re</strong>a <strong>of</strong> distribution throughout the temperate<br />
latitudes according to information assembled by Düll<br />
(1984). He <strong>re</strong>stricted the variety densa (as T. densa) to<br />
Europe, in bo<strong>re</strong>al-montane situations.<br />
Braunmiller et al. (1971) mapped for central<br />
Europe the distribution <strong>of</strong> var. inclinata as nearly<br />
uniform from the Alps in the south to the margins <strong>of</strong> the<br />
Lowland countries to the north. The var. densa was<br />
closer to the distribution <strong>of</strong> Tortella fragilis: <strong>re</strong>stricted<br />
to the mountanous highlands in the south. Düll and<br />
Meinunger (1989) give nearly identical distributions<br />
(but var. inclinata is not mapped).<br />
In Europe the ranges <strong>of</strong> Tortella flavovi<strong>re</strong>ns<br />
and T. inclinata s.l. a<strong>re</strong> so close as to appear to overlap,<br />
whe<strong>re</strong>as in North America the ranges a<strong>re</strong> disjunct from<br />
the coast <strong>of</strong> North Carolina to the G<strong>re</strong>at Lakes <strong>re</strong>gion. If<br />
T. inclinata cannot tolerate the salty conditions <strong>of</strong> the<br />
substrates that support populations <strong>of</strong> T. flavovi<strong>re</strong>ns,<br />
then it is possible the ranges a<strong>re</strong> contiguous and do not<br />
<strong>re</strong>ally overlap. However, Rubers (1973) <strong>re</strong>ported two<br />
collections in the Netherlands <strong>of</strong> T. inclinata (possibly<br />
from a single locality) in the dunes by Overveen.<br />
Extra-North American <strong>re</strong>ports <strong>of</strong> this species in<br />
South America, Asia, Africa and Australia seem<br />
problematic to some extent when compa<strong>re</strong>d to the<br />
<strong>re</strong>striction <strong>of</strong> Tortella inclinata in North America to<br />
terrain at the Wisconsinan glacial boundary. One would<br />
anticipate similar <strong>re</strong>strictions and distributional histories<br />
in other a<strong>re</strong>as <strong>of</strong> the world.<br />
The epithet "inclinata" <strong>re</strong>fers to a curving<br />
capsule, however at least some capsules <strong>of</strong> every<br />
species in the genus in the flora a<strong>re</strong>a also have inclined<br />
capsules. Some <strong>of</strong> the inf<strong>re</strong>quent North American<br />
sporophyte material shows curving capsules atop a seta<br />
that curves or is geniculate at or near the junctu<strong>re</strong> with<br />
the capsule: the two characters in combination show a<br />
striking departu<strong>re</strong> from an e<strong>re</strong>ct postu<strong>re</strong>. Haring (1938)<br />
emphasized the "capsule narrowly cylindrical, nearly<br />
straight, sube<strong>re</strong>ct" for American populations, possibly to<br />
distinguish them from European specimens. The p<strong>re</strong>sent<br />
study, however, found variation similar to European<br />
collections: examples <strong>of</strong> this species among W. P.<br />
Schimper's duplicates at BUF have capsules sube<strong>re</strong>ct,<br />
somewhat curved to strongly curved in single<br />
populations.<br />
As Crum and Anderson (1981) indicated,<br />
Tortella inclinata var. inclinata in the G<strong>re</strong>at Lakes<br />
<strong>re</strong>gion is rather <strong>re</strong>adily separated from T. tortuosa and<br />
T. fragilis, which occupy similar habitats on partially<br />
stabilized, calca<strong>re</strong>ous dune sands in the G<strong>re</strong>at Lakes<br />
<strong>re</strong>gion, by its shorter leaves that a<strong>re</strong> incurved and<br />
moderately contorted when dry with, broad, cucullate<br />
tips. Tortella humilis, which might possibly be confused<br />
with these species, has a distinct stem central strand.<br />
The absence <strong>of</strong> any quadrate, papillose adaxial<br />
epidermal cells in cross sections <strong>of</strong> the distal or middle<br />
part <strong>of</strong> the leaf will diffe<strong>re</strong>ntiate specimens <strong>of</strong> T.
inclinata var. inclinata from the th<strong>re</strong>e species just<br />
named. Specimens with an adaxial groove <strong>of</strong> elongate,<br />
smooth cells on the surface <strong>of</strong> the costa throughout the<br />
leaf and with leaves that a<strong>re</strong> not cucullate but only acute<br />
with a short mucro, may be T. inclinata var. densa<br />
instead. Thickened abaxial and adaxial superficial cell<br />
walls seen in lamina cross-section will also indicate that<br />
variety.<br />
No small, terminal propaguliferous shoots, as<br />
mentioned for English plants <strong>of</strong> Tortella inclinata var.<br />
inclinata by Smith (1978), we<strong>re</strong> observed or <strong>re</strong>cognized<br />
in North American material. Any terminal filaments<br />
proved to be associated with archegonia, and comprised<br />
the distinctive setaceous apices <strong>of</strong> perichaetial leaves.<br />
Lack <strong>of</strong> such shoots in American material may indicate<br />
that European plants could be a somewhat diffe<strong>re</strong>nt<br />
taxon. Nyholm (1989) for example, stated that in<br />
Scandinavia: "Short fragile yellow-g<strong>re</strong>en apical shoots<br />
a<strong>re</strong> characteristic for this species." Nyholm indicated<br />
that such shoots a<strong>re</strong> important in diffe<strong>re</strong>ntiating the<br />
species from T. densa and T. rigens. It is possible that<br />
these shoots a<strong>re</strong> simply elongations <strong>of</strong> the main stem<br />
axis and a<strong>re</strong> no mo<strong>re</strong> deciduous than the whorls <strong>of</strong> the<br />
var. densa which disarticulate <strong>re</strong>adily upon dissection.<br />
Tortella inclinata s.l. has up to the p<strong>re</strong>sent been<br />
the only taxon <strong>of</strong> the genus in North America to have no<br />
epidermal layer on the costa anywhe<strong>re</strong> on the leaf. Only<br />
the narrow, elongated, smooth ste<strong>re</strong>id cells a<strong>re</strong> exposed<br />
on both surfaces <strong>of</strong> the costa. In Europe, this species<br />
sha<strong>re</strong>s this characteristic with T. rigens, T. densa and T.<br />
limosella (Stirt.) Rich. & Wall. (Smith 1978). Tortella<br />
limosella is separated from T. inclinata in the British<br />
flora in part by having distal leaf cells 8–12 µm wide,<br />
whe<strong>re</strong>as cells <strong>of</strong> the latter species a<strong>re</strong> 8–10 µm. North<br />
American T. inclinata var. inclinata <strong>re</strong>gularly attains the<br />
larger cell dimensions, however. In addition to larger<br />
cells, T. limosella has thicker cell walls and these a<strong>re</strong><br />
unipapillose. It was collected once (1906) from dense<br />
patches from a single population on the seacoast in<br />
western Scotland (Smith 1978) and maybe synonymous<br />
with a mo<strong>re</strong> inclusive concept <strong>of</strong> the variability <strong>of</strong> T.<br />
inclinata s.l.<br />
Persson and Weber (1958), when they first<br />
<strong>re</strong>ported Tortella inclinata from North America,<br />
exp<strong>re</strong>ssed doubts that the p<strong>re</strong>viously described North<br />
American Barbula inclinatula C. M. & Kindb. was<br />
distinct from it. Dixon (1924) <strong>re</strong>ported a diffe<strong>re</strong>nt<br />
ecological and distributional <strong>re</strong>gime for European T.<br />
inclinata: "calca<strong>re</strong>ous banks and rocks, usually in<br />
mountainous districts." North American material, for<br />
example, never grows on rocks, but T. inclinata var.<br />
densa does.<br />
Crundwell and Nyholm (1962) stated that the<br />
Müller and Kindberg type <strong>of</strong> Tortella inclinatula was<br />
identical with European T. inclinata as we<strong>re</strong> two<br />
additonal specimens, one from Ontario and from British<br />
Columbia. Stee<strong>re</strong> and Scotter (1978) still, however,<br />
exp<strong>re</strong>ssed some hesitation based on a sense that the<br />
perichaetial leaves <strong>of</strong> the type <strong>of</strong> Barbula inclinatula<br />
we<strong>re</strong> diffe<strong>re</strong>nt from European material. "Macoun's 190<br />
32<br />
in the National Museum <strong>of</strong> Canada (CANM) has<br />
perichaetial leaves that a<strong>re</strong> conspicuously larger and<br />
mo<strong>re</strong> hyaline than those on European material<br />
examined" (Stee<strong>re</strong> & Scotter 1978).<br />
Although Macoun 190 was not available in the<br />
loan <strong>re</strong>ceived from CANM, th<strong>re</strong>e other North American<br />
fruiting specimens we<strong>re</strong> examined: Alberta, John<br />
Macoun, June 27, 1904 (CANM); B.C., Lake <strong>of</strong><br />
Hanging Glaciers, Wilmer, July 21, 1928, MacFadden<br />
4252 (NY); and also what is appa<strong>re</strong>ntly an isotype <strong>of</strong><br />
Tortella inclinatula: B.C., Illicillewaet near Revelstoke,<br />
May 27, 1890, Macoun 188 (NY). These we<strong>re</strong><br />
compa<strong>re</strong>d with fruiting specimens <strong>of</strong> T. inclinata from<br />
Europe (Strasbourg in western France, Switzerland and<br />
Saxony in eastern Germany) among the W. P. Schimper<br />
duplicates at BUF. No significant transoceanic<br />
diffe<strong>re</strong>nces between the perichaetial leaves <strong>of</strong> these<br />
plants we<strong>re</strong> found. None <strong>of</strong> the American perichaetial<br />
leaves exceeded those <strong>of</strong> the European ones excepting<br />
one specimen (Macoun) in which the leaves we<strong>re</strong><br />
perhaps 0.4 mm longer, an unimp<strong>re</strong>ssive magnitude <strong>of</strong><br />
diffe<strong>re</strong>nce. The laminae <strong>of</strong> the perichaetial leaves appear<br />
white-hyaline in all specimens even at low<br />
magnification. If the American material is diffe<strong>re</strong>nt<br />
from European specimens, the perichaetial leaves a<strong>re</strong><br />
not decisive.<br />
The strikingly diffe<strong>re</strong>ntiated perichaetial leaves<br />
<strong>of</strong> Tortella inclinata var. inclinata only occur in<br />
association with fertilized archegonia. When adjacent<br />
perichaetiate unfertilized stems in specimens with<br />
fertilized stems we<strong>re</strong> examined, the perichaetial leaves<br />
we<strong>re</strong> less distinct from the stem leaves—for example,<br />
they we<strong>re</strong> not longer. Numerous specimens <strong>of</strong><br />
unfertilized perichaetiate plants <strong>of</strong> the var. densa from<br />
North America showed much variability <strong>of</strong> the<br />
perichaetial leaves but nothing to distinguish them from<br />
those <strong>of</strong> unfertilized, perichaetiate var. inclinata.<br />
In Tortella inclinata var. inclinata the<br />
setaceous perichaetial leaves may be conspicuous on<br />
dry stems whe<strong>re</strong> they rise mo<strong>re</strong> stiffly above the curled<br />
stem leaves—as is true <strong>of</strong> those <strong>of</strong> T. alpicola, T.<br />
fragilis and T. tortuosa. Such perichaetiate plants,<br />
though uncommon, a<strong>re</strong> easy to confuse with sterile or<br />
fertile T. fragilis, but the setaceous leaves <strong>of</strong> that species<br />
have propaguloid modifications in the apex whether<br />
bar<strong>re</strong>n or fertile. Fertile T. inclinata var. inclinata has<br />
also been confused with T. tortuosa but in the latter<br />
species the lower leaves a<strong>re</strong> also long-mucronate. The<br />
lower leaves in T. inclinata var. inclinata a<strong>re</strong> all<br />
<strong>re</strong>latively blunt or cucullate.<br />
The p<strong>re</strong>sence in some perichaetial leaves (with<br />
fertilized archegonia) <strong>of</strong> an interrupted border <strong>of</strong><br />
elongate, thick-walled smooth cells in the distal portion<br />
<strong>of</strong> the leaf is <strong>re</strong>miniscent <strong>of</strong> perichaetial leaves <strong>of</strong><br />
Tortella tortuosa whe<strong>re</strong> this character is mo<strong>re</strong><br />
pronounced. This characteristic is very important in the<br />
subulate-propaguloid leaves <strong>of</strong> both sterile and fertile<br />
(perichaetial) leaves <strong>of</strong> T. fragilis and seems to<br />
contribute to the rigidity <strong>of</strong> the leaves that possess these<br />
borders in all th<strong>re</strong>e species.
In her key to the species <strong>of</strong> Tortella in North<br />
America north <strong>of</strong> Mexico, Haring separated T. inclinata<br />
from T. humilis and T. flavovi<strong>re</strong>ns by cucullate leaf<br />
apices and the leaves "very concave." Neither Macoun<br />
and Kindberg (1892), or Haring (1938) compa<strong>re</strong>d T.<br />
inclinatula with T. inclinata <strong>of</strong> Europe, as noted by<br />
Persson and Weber (1958). The cucullate leaves <strong>of</strong> T.<br />
inclinata in Europe (Sweden) a<strong>re</strong> <strong>re</strong>ported as critical to<br />
distinguish that species from T. densa and T. rigens,<br />
which a<strong>re</strong> "narrowed into a sharp point" (Nyholm 1989).<br />
Cucullate leaf apices characterize the var. inclinata<br />
p<strong>re</strong>sented he<strong>re</strong>.<br />
An ext<strong>re</strong>me <strong>of</strong> this kind <strong>of</strong> apex is shown in a<br />
specimen from Minnesota that has leaves broader than<br />
those <strong>of</strong> typical T. inclinata and apices that a<strong>re</strong><br />
completely cucullate. Latzel (1934, p. 174) described a<br />
variety <strong>of</strong> T. inclinata from Hungary as var. mutica:<br />
"Folia etiam humecta partim fe<strong>re</strong> fistulosa, obtusa vel<br />
obtusiuscula, costa ante apicem vel in apice<br />
evanescens." The Minnesota plants possess fistulose<br />
leaves in the sense that fistulose implies a tube with one<br />
end closed. The description suits this specimen, except<br />
the costae a<strong>re</strong> both percur<strong>re</strong>nt and excur<strong>re</strong>nt as delicate<br />
mucros, many <strong>of</strong> which a<strong>re</strong> eroded. Just as the<br />
acuminate-leaved plants have long-stems, this strongly<br />
obtuse-cucullate plant has short ones. An even better<br />
<strong>re</strong>p<strong>re</strong>sentation <strong>of</strong> the var. mutica is <strong>re</strong>p<strong>re</strong>sented in a<br />
specimen from British Columbia that is better identified<br />
as T. inclinata var. densa (see below) at least by the<br />
thick cell walls and orange coloration. The var. mutica<br />
seems not worthy <strong>of</strong> <strong>re</strong>cognition, me<strong>re</strong>ly <strong>re</strong>p<strong>re</strong>senting a<br />
sporadic unimportant ext<strong>re</strong>me <strong>of</strong> variation.<br />
The diffe<strong>re</strong>ntiated proximal cell <strong>re</strong>gion in<br />
Tortella inclinata is short among its congeners. Haring<br />
(1938) for example indicated it as 1/5–1/4 the leaf<br />
length, whe<strong>re</strong>as it is longer (1/4–1/3) in both T. humilis<br />
and T. flavovi<strong>re</strong>ns. This short proximal cell <strong>re</strong>gion is<br />
displayed in at least some leaves <strong>of</strong> T. inclinata var.<br />
inclinata and var. densa. Other leaves on longer stems<br />
in T. inclinata occupy mo<strong>re</strong> <strong>of</strong> the leaf length, to 1/3,<br />
and in some leaves the <strong>re</strong>gion appears to extend quite<br />
high on the margin in all th<strong>re</strong>e closely <strong>re</strong>lated species.<br />
6b. TORTELLA INCLINATA VAR. DENSA Plate 9<br />
Tortella inclinata var. densa (Lor. & Mol.) Eckel,<br />
comb. nov. [note post publ, hom. superf.]<br />
Barbula inclinata var. densa Lor. & Mol. in<br />
Lo<strong>re</strong>ntz, Moosstud. 90. 1864,<br />
basionym. Type: Germany, Bayern,<br />
Oberbayern, Landk<strong>re</strong>is Garmisch-<br />
Partenkirchen: "Platt an der Zugspitz,<br />
6000–6500'; 10. Juli 1862, L.<br />
Molendo" (M—lectotype).<br />
Tortella inclinata fo. compacta ROll,<br />
Hedwigia 56: 142. 1915.<br />
Tortella densa (Lor. & Mol.) Crundw. & Nyh.,<br />
Trans. Brit. Bryol. Soc. 4(2): 188. 1,<br />
a–c. 1962.<br />
33<br />
Tortella tortuosa fo. curta Alberts.<br />
Österplana hed ett alvarområde på<br />
kinnekulle. Upsala. 207. 1946. [name<br />
invalid: without Latin description.<br />
Albertson meant to use the form-name<br />
provisionally ("provisoriskt": 193.)]<br />
Plants in dense sods or cushions <strong>of</strong> high, e<strong>re</strong>ct stems,<br />
dull pale g<strong>re</strong>en with <strong>re</strong>ddish highlights (coppery-sheen)<br />
in youngest leaves at stem apex, dull brownish-orange<br />
below or throughout, elongate, not rosulate. Stems (0.5–<br />
)1.5–2 cm high, central strand absent, longer stems with<br />
multiple branches, elongate lateral shoots with<br />
primordial or small <strong>re</strong>duced leaves occasionally p<strong>re</strong>sent;<br />
distal stem with inconspicuous rufous radiculosetomentum<br />
hidden at the base <strong>of</strong> the leaf axils, this<br />
sometimes appearing absent in well-developed forms,<br />
large coarse rhizoids scatte<strong>re</strong>d along the stem,<br />
sometimes concentrated at the bases <strong>of</strong> whorls. Stem<br />
leaves somewhat stiff, closely and densely foliose,<br />
appearing imbricated, larger, broader and nearly<br />
uniformly e<strong>re</strong>ct at the base and smaller and narrower at<br />
the stem apex and mo<strong>re</strong> ir<strong>re</strong>gularly contorted the<strong>re</strong> when<br />
dry, most middle leaves loosely curled in a counterclockwise<br />
di<strong>re</strong>ction when dry, or counter-clockwise<br />
below and clockwise above, giving a rope-like<br />
(funaliform) appearance to the habit, e<strong>re</strong>ct and<br />
sp<strong>re</strong>ading when moist, individual leaves as seen from<br />
above twisted clockwise, shortly triangular-lanceolate<br />
and tape<strong>re</strong>d from the base, tubulose (margins broadly<br />
incurved), variously strongly keeled-concave or broadly<br />
channeled across the leaf above, (1–)1.5–2 mm long,<br />
not undulate; base shortly ovate or sharply ovate below<br />
a cinctu<strong>re</strong> at the junctu<strong>re</strong> <strong>of</strong> distal laminal cells;<br />
margins c<strong>re</strong>nulate-papillose, apex cucullate to concaveacute<br />
to acuminate; costa excur<strong>re</strong>nt into a slender, sharp<br />
mucro <strong>of</strong> 5–7(–9) cells in acuminate leaves confluent<br />
with the lamina, cove<strong>re</strong>d on the adaxial surface by<br />
elongate, smooth-walled cells throughout the leaf<br />
length, shape in section circular distally to lunate in<br />
middle and proximal <strong>re</strong>gions, the adaxial surface convex<br />
to concave in the median leaf <strong>re</strong>gion, especially when<br />
the<strong>re</strong> a<strong>re</strong> bistratose cells at junction <strong>of</strong> lamina with<br />
costa, adaxial epidermis absent, abaxial and adaxial<br />
ste<strong>re</strong>ids p<strong>re</strong>sent, somewhat mo<strong>re</strong> massive than in T.<br />
inclinata, costa and adjacent lamina in cross section<br />
<strong>of</strong>ten bistratose in the middle <strong>re</strong>gion <strong>of</strong> the leaf;<br />
proximal laminal cells sharply diffe<strong>re</strong>ntiated, proximal<br />
angle steep, although filling only the proximal fifth or<br />
less <strong>of</strong> the leaf, the cells in some leaves tend to rise<br />
somewhat high on the margins, smooth, hyaline,<br />
somewhat thick-walled (not lax) near junction with<br />
distal laminal cells, marginal cells somewhat <strong>re</strong>duced in<br />
size, sharply c<strong>re</strong>nulate with high papillae to smooth and<br />
c<strong>re</strong>nulate by projecting cell walls, usually<br />
undiffe<strong>re</strong>ntiated, occasionally on longer leaves with a<br />
marginal border <strong>of</strong> elongate (2–3:1), thinner-walled,<br />
smooth cells extending distally from the hyaline<br />
proximal cell <strong>re</strong>gion; distal laminal cells somewhat<br />
larger towards the apex, obscu<strong>re</strong>d by thick superficial
cell walls and massive pedestaled coroniform papillae,<br />
the papillae sometimes <strong>re</strong>duced and the lumen capped<br />
by a smooth, thick salient, 8–10 µm, in one collection<br />
with some cells <strong>re</strong>aching 14 µm. In cross section the<br />
abaxial and adaxial cell walls thicker than the crosswalls<br />
together with abaxial and adaxial papillae, both<br />
thicker than the height <strong>of</strong> the lumen itself. Asexual<br />
<strong>re</strong>production: sterile lateral shoots with minute or<br />
primordial leaves distant on the axis developing into<br />
foliose stems, possibly for vegetative dispersal. Sexual<br />
condition: dioicous. Perigonia in sessile buds at stem<br />
apices, inner perigonial bracts ovate and abruptly<br />
apiculate, scarcely longer than the antheridia, 0.5 mm<br />
long. Perichaetia as many as six on a stem, the stem<br />
elongating by multiple, successive, short subperichaetial<br />
innovations; outer perichaetial leaves undiffe<strong>re</strong>ntiated<br />
and appearing mo<strong>re</strong> acute than stem leaves by closely<br />
infolded distal margins; inner perichaetial leaves<br />
variable, equal to or shorter than surrounding leaves,<br />
diffe<strong>re</strong>ntiated as narrow, abb<strong>re</strong>viated laminae ending in<br />
a long, subulate awn above an inflated, sheathing<br />
hyaline base. Sporophytes: no fruiting material seen.<br />
A species <strong>of</strong> temperate and bo<strong>re</strong>al associations<br />
on sandy soil <strong>of</strong> rocky uplands or hills, rock slides, soil<br />
at the base <strong>of</strong> sandstone outcrops, cliff c<strong>re</strong>vices, ledges<br />
and bases in mesic to moist stations, probably<br />
associated closely with old post-glacial alluvium in<br />
drainage basins <strong>of</strong> lakes and rivers; in Europe on Baltic<br />
alvars and in montane or alpine stations; in North<br />
America 934–1560 m., B.C., N.W.T., Alaska, Mich,<br />
Wisc.; Europe.<br />
Herbaria examined: BUF, CANM, NY, UBC.<br />
Of the five specimens <strong>of</strong> var. densa in<br />
Molendo's herbarium (M—comm. H. Hertel), one (see<br />
above) was selected as lectotype, being collected befo<strong>re</strong><br />
the date <strong>of</strong> publication and fitting well the original<br />
authors' concept. It is beautifully <strong>re</strong>p<strong>re</strong>sented by copious<br />
material giving both short stems (0.5 cm) and long (4<br />
cm), described on the label as var. "densa, foliis b<strong>re</strong>vius<br />
acuminatis, statura compacta robustio<strong>re</strong> insignis." The<br />
Latin implies the<strong>re</strong> a<strong>re</strong> other variations that a<strong>re</strong> mo<strong>re</strong><br />
long-acuminate. The leaves on the specimen a<strong>re</strong><br />
intermediate-acuminate, without the long, narrow apices<br />
with long mucros <strong>of</strong> many specimens seen. It conforms<br />
perfectly with material from stations in northwestern<br />
North American, especially in the strongly concave<br />
adaxial surface <strong>of</strong> the costa in section with multistratose<br />
a<strong>re</strong>as beside the costa (cf. illustration, Plate 9). The<br />
European specimen exhibits the ext<strong>re</strong>mely deep sods<br />
that the species <strong>of</strong>ten attains in the Alps, compa<strong>re</strong>d to<br />
shallower sods in the comparatively drier mountains <strong>of</strong><br />
North America (Rocky Mountains).<br />
Specimens <strong>of</strong> Tortella inclinata having<br />
substrates not di<strong>re</strong>ctly associated with alluvium may<br />
<strong>re</strong>veal var. densa which seems to be associated with<br />
older, stable habitats, rather than colonizing <strong>re</strong>latively<br />
mo<strong>re</strong> <strong>re</strong>cent ones, such as does the var. inclinata. While<br />
European descriptions <strong>of</strong> T. inclinata include sandy soil<br />
associated with river banks, they also include walls and<br />
rocks (Dema<strong>re</strong>t & Castagne 1964), stations not known<br />
34<br />
for T. inclinata var. inclinata in North America. Most<br />
North American specimens a<strong>re</strong> identified as T. inclinata<br />
if bearing a cucullate apex, and T. tortuosa if an<br />
acuminate one.<br />
Braunmiller et al. (1971) discussed Tortella<br />
densa as a <strong>re</strong>latively new species after the publication<br />
by Crundwell and Nyholm (1962). After examination <strong>of</strong><br />
a series <strong>of</strong> specimens, these authors had appa<strong>re</strong>ntly<br />
decided it to be a good species, independently noting the<br />
homogeneous torsion <strong>of</strong> the leaves in well developed<br />
plants, <strong>re</strong>miniscent <strong>of</strong> that <strong>of</strong> Grimmia funalis Schimp.<br />
The authors associated the species with (calca<strong>re</strong>ous)<br />
rock c<strong>re</strong>vices, unlike the stations noted above in var.<br />
inclinata and they felt hinde<strong>re</strong>d in their generalities due<br />
to the lack <strong>of</strong> adequate herbarium specimens or their<br />
mistaken inclusion in the circumscription <strong>of</strong> other<br />
species. A station found in Bavaria by Paul (1943) is<br />
noteworthy for its occurrance on glacial moraine, "one<br />
<strong>of</strong> the richest stations for circumalpine plants in the<br />
foothills <strong>of</strong> the Alps...the appearance <strong>of</strong> the species<br />
the<strong>re</strong> suggests a glacial foothills dispersal."<br />
The occur<strong>re</strong>nce <strong>of</strong> this variety in the Alps <strong>of</strong><br />
Europe leads one to expect it to occur in the Rocky<br />
Mountains in North America south <strong>of</strong> the Canadian<br />
border. North American stations, however, a<strong>re</strong> as<br />
hitherto <strong>re</strong>ported for Tortella inclinata var. inclinata,<br />
that is, within the southern and western limit <strong>of</strong><br />
Wisconsinan glaciation, but not south <strong>of</strong> it. The<br />
specimens on which the North American occur<strong>re</strong>nce <strong>of</strong><br />
var. densa is he<strong>re</strong> based perhaps fail to show the full<br />
range <strong>of</strong> characters possible, based on ext<strong>re</strong>mes<br />
examined in European collections mainly in the g<strong>re</strong>ater<br />
deg<strong>re</strong>e <strong>of</strong> acumination, but a<strong>re</strong> very like the type<br />
specimen. Re-examination <strong>of</strong> specimens <strong>of</strong> T. tortuosa<br />
in the Rocky Mountains may ultimately <strong>re</strong>veal a mo<strong>re</strong><br />
widesp<strong>re</strong>ad distribution <strong>of</strong> T. inclinata var. densa on this<br />
continent.<br />
The single <strong>re</strong>port for Tortella inclinata in the<br />
Arctic was a citation by Stee<strong>re</strong> (1978) <strong>of</strong> a specimen<br />
<strong>re</strong>ported from the Brooks Range in Alaska, collected by<br />
Louis Jordal (2050, CANM; see specimen citation<br />
above) and published by Miller (1976). The specimen<br />
was originally identified as Tortella tortuosa but was<br />
<strong>re</strong>determined by Miller with the following note:<br />
"probably T. inclinata...but material not typical. Distal<br />
leaf cells small, ca. 10 µm; apices <strong>of</strong> even young leaves<br />
scarcely cucullate" (det. April 1975). Crum, in 1964,<br />
and Zander (1997) in a <strong>re</strong>cent t<strong>re</strong>atment <strong>of</strong> Tortella for<br />
Arctic North America, also examined the specimen and<br />
determined it to be that species. However, the stems a<strong>re</strong><br />
<strong>re</strong>ddish-orange, the leaves a<strong>re</strong> densely foliose, in cross<br />
section they have thickened superficial cell walls on<br />
both sides <strong>of</strong> the leaf section, forming pedestals on<br />
which the papillae a<strong>re</strong> developed, and a<strong>re</strong> <strong>re</strong>determined<br />
he<strong>re</strong> to be T. inclinata var. densa. Most <strong>of</strong> the leaves a<strong>re</strong><br />
acuminate, rather than cucullate, perhaps because the<br />
stems a<strong>re</strong> richly perichaetiate.<br />
Even in some specimens with short stems (less<br />
than 0.5 mm), the very thick superficial walls in<br />
transverse section and acute apices and orange color
we<strong>re</strong> diagnostic (Vitt 18784, citation below). The Jordal<br />
specimen is most like the discussion <strong>of</strong> Tortella densa<br />
(as T. tortuosa forma curta) by Albertson (1946). The<br />
leaves a<strong>re</strong> narrowly acuminate, most only subcucullate,<br />
with marginal borders extending from the proximal<br />
<strong>re</strong>gion nearly to the apex.<br />
Another specimen from Arctic Alaska, cited by<br />
Stee<strong>re</strong> (1978) as Tortella tortuosa and by Zander (1997)<br />
as T. inclinata from the Ambler River a<strong>re</strong>a (Brooks<br />
Range, Lewis 1768; see citation below), is also the var.<br />
densa by the same criteria. These plants have perigonia.<br />
The specimen includes stems with short, acute leaves<br />
with short mucros, mostly eroded, in dense e<strong>re</strong>ct tufts,<br />
with papillae with high salients. The leaf cross-section<br />
shows a strongly keeled leaf with the adaxial ste<strong>re</strong>id<br />
layer exposed throughout the leaf. The label data<br />
indicate the collection came from a "dry calca<strong>re</strong>ous<br />
ridge," and not from sandy riverine deposits typical <strong>of</strong><br />
T. inclinata. The stems a<strong>re</strong> coated with sandy particles<br />
and the<strong>re</strong> a<strong>re</strong> horizontal layers <strong>of</strong> what appear to be<br />
deposits made when the collections we<strong>re</strong> in wet<br />
conditions, perhaps <strong>of</strong> high water from the Ambler<br />
River.<br />
As these two specimens comprise the only<br />
<strong>re</strong>ports <strong>of</strong> Tortella inclinata from Arctic North America,<br />
the var. inclinata is conside<strong>re</strong>d he<strong>re</strong> to be excluded from<br />
that <strong>re</strong>gion.<br />
Crundwell and Nyholm (1962) described<br />
Tortella densa as tall, to 4 cm. Limpricht (1890)<br />
described stems to 8 cm in deep sods. Perhaps the most<br />
telling description, with <strong>re</strong>spect to North American<br />
populations, is <strong>of</strong> the leaves on the stem: "in well-grown<br />
shoots twisted slightly round the stem in a manner<br />
rather like that in Grimmia funalis." The leaves a<strong>re</strong><br />
hardly crisped excepting the youngest at the stem apex.<br />
The species is "widely distributed in western, northern<br />
and central Europe. Although only the Norwegian<br />
locality is north <strong>of</strong> the Arctic Circle all the central<br />
European ones a<strong>re</strong> from mountains, many from high<br />
altitudes." Limpricht (1890) described it as a very<br />
distinctive high-alpine form growing above 2,000 m in<br />
Europe.<br />
Crundwell and Nyholm (1962) <strong>re</strong>ported that<br />
"We have seen rather much North American material <strong>of</strong><br />
Tortella, and if T. densa occurs the<strong>re</strong> it must certainly<br />
be ra<strong>re</strong>." Note that all <strong>of</strong> the specimens cited above we<strong>re</strong><br />
collected after their 1962 article.<br />
In North America, Tortella inclinata var.<br />
inclinata is usually said to be confined to a rather<br />
narrowly defined substrate: essentially rather <strong>re</strong>cently,<br />
hence partially, stabilized alluvium associated with<br />
beaches in the G<strong>re</strong>at Lakes and (perhaps <strong>re</strong>cently)<br />
abandoned river channels (Haring 1938; Crum &<br />
Anderson 1981). "Recent" he<strong>re</strong> <strong>re</strong>fers to Holocene, or<br />
post-glacial sediments. Specimens hitherto labeled as T.<br />
inclinata in North American herbaria, however, also<br />
indicate their occur<strong>re</strong>nce on limestone pavements<br />
(alvar) not associated with alluvial sediments. These<br />
particular specimens proved to be T. rigens (see<br />
discussion below).<br />
35<br />
Another suite <strong>of</strong> specimens, mostly <strong>re</strong>cently<br />
collected in the less accessible northern a<strong>re</strong>as <strong>of</strong> Alaska,<br />
British Columbia and the Northwest Territories,<br />
<strong>re</strong>vealed a third set <strong>of</strong> substrates for var. densa as rock<br />
c<strong>re</strong>vices in mo<strong>re</strong> elevated stations that those <strong>of</strong><br />
p<strong>re</strong>viously <strong>re</strong>ported stations <strong>of</strong> Tortella inclinata. Even<br />
though among rock, these stems we<strong>re</strong> embedded in<br />
sand-sized particles, indicating some association with<br />
localized watersheds: riverine environments with a<br />
historical character, perhaps with once higher water<br />
levels or with mo<strong>re</strong> <strong>re</strong>cent st<strong>re</strong>am channel abandonment,<br />
in post-glacial fens. Tortella inclinata was first<br />
discove<strong>re</strong>d in North America in abandoned river beds<br />
"along old channels <strong>of</strong> the Illicillewaet" in British<br />
Columbia (Macoun and Kindberg 1892)—a perhaps<br />
mo<strong>re</strong> <strong>re</strong>cently abandoned situation, as might be dunes<br />
cor<strong>re</strong>lated with <strong>re</strong>latively <strong>re</strong>cent historic <strong>re</strong>ductions in<br />
lake water levels. Such upland stations tend to suggest a<br />
<strong>re</strong>fugial character.<br />
Stee<strong>re</strong> (1976: 54) in his discussion on the<br />
ecological <strong>re</strong>lationship <strong>of</strong> light to bryophytes in Arctic<br />
Alaska <strong>re</strong>ported that: "The distribution <strong>of</strong> tufts <strong>of</strong> mats<br />
<strong>of</strong> bryophytes on a vertical rock face seems mo<strong>re</strong> to<br />
<strong>re</strong>flect the p<strong>re</strong>sence <strong>of</strong> water drainage channels than a<br />
<strong>re</strong>sponse to the intensity <strong>of</strong> light. In Arctic Alaska, a few<br />
species <strong>of</strong> bryophytes a<strong>re</strong> generally <strong>re</strong>stricted in their<br />
habitat to deep rock c<strong>re</strong>vices. However, this p<strong>re</strong>fe<strong>re</strong>nce<br />
appears to indicate a <strong>re</strong>qui<strong>re</strong>ment for the higher<br />
humidity that occurs out <strong>of</strong> the wind and di<strong>re</strong>ct sun, and<br />
not a <strong>re</strong>action to light intensity, per se....My evidence<br />
for this conclusion is that in mo<strong>re</strong> temperate climates<br />
with normally higher atmospheric humidity, these very<br />
same species may grow in the open on the trunks <strong>of</strong><br />
t<strong>re</strong>es and on the sides <strong>of</strong> rocks, not in full sunlight, but<br />
certainly not <strong>re</strong>stricted to c<strong>re</strong>vices for protection against<br />
drying winds."<br />
Tortella densa "In the British Isles and in<br />
Sweden...is a plant <strong>of</strong> rock c<strong>re</strong>vices and <strong>of</strong> rocks with a<br />
thin covering <strong>of</strong> soil. We have never seen it on sand<br />
dunes. It f<strong>re</strong>quently grows in the same habitat as T.<br />
tortuosa" (Crundwell & Nyholm 1962). In Scandinavia<br />
it grows "up to 4 cm high on calca<strong>re</strong>ous rocks and soil"<br />
(Nyholm 1989). "...In the alvar vegetation <strong>of</strong> Öland and<br />
Gotland, whe<strong>re</strong> the underlying limestone is cove<strong>re</strong>d by<br />
only a very thin layer <strong>of</strong> soil [T. densa and T. inclinata]<br />
<strong>of</strong>ten occur together, associated with T. tortuosa, T.<br />
fragilis and T. rigens. These five species f<strong>re</strong>quently<br />
grow in mixed tufts, without intermediates" (Crundwell<br />
& Nyholm 1962). Such a community has so far not been<br />
<strong>re</strong>ported for the alvars <strong>of</strong> the G<strong>re</strong>at Lakes <strong>re</strong>gion (see<br />
Catling & Brownell 1995) but may be anticipated. One<br />
may also wonder whether these taxa might not be<br />
p<strong>re</strong>sent in the extensive limestone plateaus or<br />
geologically classic karst a<strong>re</strong>as <strong>of</strong> the Adriatic.<br />
These species, but especially Tortella inclinata,<br />
T. densa and T. rigens appa<strong>re</strong>ntly have close<br />
cor<strong>re</strong>lations with diffe<strong>re</strong>nt substrates. When the latter<br />
th<strong>re</strong>e a<strong>re</strong> said to grow in alvar, it must be borne in mind<br />
that the<strong>re</strong> a<strong>re</strong> numerous kinds <strong>of</strong> alvar vegetation,<br />
depending on the depth <strong>of</strong> the soil and most particularly
whether it is a wet or dry alvar (classification by Catling<br />
& Brownell 1995). Label data is usually insufficient<br />
from alvar <strong>re</strong>gions to specify species p<strong>re</strong>fe<strong>re</strong>nces for<br />
specific ecological <strong>re</strong>gimes.<br />
The most striking characteristic <strong>of</strong> the western<br />
North American specimens <strong>re</strong>cently collected from<br />
rocky substrates was their tall, densely foliose,<br />
numerously branched stems in <strong>re</strong>gimented tufts, unlike<br />
T. inclinata whose stems a<strong>re</strong> usually smaller and<br />
indistinct, little branched, the leaves mo<strong>re</strong> chaotically<br />
twisted around the stem and half buried in the debris.<br />
The new specimens a<strong>re</strong> noted by their darker (fuscous to<br />
black below) or mo<strong>re</strong> highly colo<strong>re</strong>d (orange) aspect,<br />
stiffer leaves, many or most narrowly acute yet still<br />
inrolled so that a subcucullate aspect to the leaf apex<br />
could be identified, a <strong>re</strong>latively orderly rope-like<br />
disposition <strong>of</strong> the leaves on dry stems and peculiar<br />
distinctly thickened superficial cell walls. Yet the<br />
specimens we<strong>re</strong> clearly <strong>re</strong>lated to T. inclinata by <strong>re</strong>ason<br />
<strong>of</strong> the absence <strong>of</strong> quadrate, papillose cells on the adaxial<br />
costa surface, tubulose leaves yielding cucullate apices<br />
on many leaves, high, sharp papillae, especially if that<br />
species we<strong>re</strong> conside<strong>re</strong>d to be a depauperate form <strong>of</strong> the<br />
specimens from rocks.<br />
Schimper (1855) described Tortella inclinata<br />
stems as "fasciculato-ramosae," or branched in fascicles,<br />
and "densissime foliosae," very densely foliose—<br />
characters not p<strong>re</strong>sently associated with T. inclinata,<br />
which is scarcely branched and only loosely foliose, but<br />
which a<strong>re</strong> characteristic <strong>of</strong> T. densa. Nyholm (1989)<br />
described the leaves <strong>of</strong> T. densa as "densely and<br />
homogeneously arranged along the stem." The substrate<br />
is described as calca<strong>re</strong>ous soil and limestone pavement,<br />
but the latter substrate in North America is so far<br />
<strong>re</strong>served for Tortella rigens. The substrate <strong>of</strong><br />
European material (England) <strong>of</strong> Tortella densa is<br />
"shallow soil on limestone rocks and in c<strong>re</strong>vices" (Smith<br />
1978). Smith indicated that the plants a<strong>re</strong> not tomentose.<br />
He wrote that the lower leaves a<strong>re</strong> straight or slightly<br />
curved and narrowly lanceolate.<br />
Tortella densa was originally described as a<br />
variety <strong>of</strong> T. inclinata (i.e. Barbula inclinata var. densa<br />
Lor. et Mol.). Tortella densa was provisionally<br />
described by Albertson (1946) as a form <strong>of</strong> Tortella<br />
tortuosa ("forma curta"), and not thought to <strong>re</strong>semble<br />
Tortella inclinata or T. rigens, which it does, however,<br />
by <strong>re</strong>ason <strong>of</strong> the smooth, elongate cells on the adaxial<br />
surface <strong>of</strong> the costa throughout the leaf and by other<br />
characters so ably described by Crundwell and Nyholm<br />
(1962).<br />
Albertson (1946) described his form as "leaf<br />
short (3–4 mm), s<strong>of</strong>t [i.e. not rigid], brownish g<strong>re</strong>en,<br />
dull, not gradually tapering to a cucullate apex, as a<br />
rule, with a hyaline border and an <strong>of</strong>ten toothed, manycelled<br />
mucro composed <strong>of</strong> the excur<strong>re</strong>nt costa, many<br />
however, <strong>of</strong>ten a<strong>re</strong> broken <strong>of</strong>f [som dock <strong>of</strong>ta är<br />
avbruten]. Leaf cells small (7–10 µm broad), very<br />
obscu<strong>re</strong> and without distinct cell walls due to the<br />
densely situated papillae."<br />
36<br />
A specimen seen from Sweden determined<br />
by Albertson showed leaf margins c<strong>re</strong>nulated by<br />
extension <strong>of</strong> the leaf cells. These appea<strong>re</strong>d to be smooth<br />
mo<strong>re</strong> by <strong>re</strong>ason <strong>of</strong> erosion <strong>of</strong> the papillae than that they<br />
do not occur. Inspection <strong>of</strong> several additional specimens<br />
shows that <strong>of</strong>ten the papillae a<strong>re</strong> not developed on<br />
various lengths <strong>of</strong> the margin, the marginal walls a<strong>re</strong><br />
smooth.<br />
The border is a distal extension <strong>of</strong> the top <strong>of</strong><br />
the proximal cell <strong>re</strong>gion, but not composed <strong>of</strong> the<br />
elongate, lax, hyaline cells <strong>of</strong> the base. Rather, these a<strong>re</strong><br />
<strong>of</strong> short-quadrate smooth cells best exposed on the<br />
longest leaves on the stem and can extend most <strong>of</strong> the<br />
length <strong>of</strong> the leaf.<br />
In northern Europe the specimens <strong>of</strong> T. densa<br />
a<strong>re</strong> described as having leaves "lanceolate, distal part<br />
gradually narrowed into [a] sharp point" (Nyholm 1989)<br />
and "narrowly lanceolate to linear-lanceolate, gradually<br />
tapering to acuminate apex" (Smith 1978). Limpricht<br />
(1890) described the plants as characteristic <strong>of</strong> the high<br />
Alps (1900–2470 m). They a<strong>re</strong> diffe<strong>re</strong>nt from Tortella<br />
inclinata by their very high and dense turves (to 8 cm)<br />
which a<strong>re</strong> not tomentose. The leaves a<strong>re</strong> shorter, mo<strong>re</strong><br />
firm (or rigid). When wet, they differ by being e<strong>re</strong>ctsp<strong>re</strong>ading,<br />
rather than inflexed (eingebogen) above. In<br />
North American specimens the tomentum is <strong>re</strong>duced<br />
and hidden in the leaf axils, much like T. tortuosa var.<br />
arctica.<br />
The variety inclinata in North America appears<br />
to be a <strong>re</strong>duced form <strong>of</strong> the mo<strong>re</strong> wide-sp<strong>re</strong>ad variety<br />
densa: the leaves a<strong>re</strong> shorter (2–3 mm), so they a<strong>re</strong> less<br />
likely to show the marginal border in the longer leaves.<br />
Shorter leaves a<strong>re</strong> cucullate (see youngest leaves <strong>of</strong> var.<br />
densa which a<strong>re</strong> <strong>of</strong>ten cucullate or naviculate). Var.<br />
inclinata has fewer branches, the stem is shorter, it has<br />
no lateral proliferations although in Europe the<strong>re</strong> may<br />
be apical ones, it has thin walls. When the walls a<strong>re</strong><br />
thin, the cells appear bigger (to 12 µm). When they a<strong>re</strong><br />
thick, as in var. densa, they appear to be smaller and<br />
obscu<strong>re</strong>. Small plants a<strong>re</strong> less highly colo<strong>re</strong>d, just like<br />
the younger leaves and plants <strong>of</strong> var. densa. All <strong>of</strong> this<br />
is paralleled in Tortella tortuosa and its variety arctica.<br />
The var. arctica is mo<strong>re</strong> densely foliose with mo<strong>re</strong><br />
branches at the apex, thickened cell walls and mo<strong>re</strong><br />
color (orange). F<strong>re</strong>quently the papillae a<strong>re</strong> <strong>re</strong>duced<br />
when the cell walls a<strong>re</strong> thickened. For the association <strong>of</strong><br />
<strong>re</strong>dness with Arctic conditions see Stee<strong>re</strong>'s (1976)<br />
discussion under T. tortuosa var. arctica above.<br />
The var. inclinata <strong>of</strong> Europe is described as<br />
tomentose, and the var. densa as without tomentum. In<br />
North American populations the smaller stems <strong>of</strong> either<br />
variety tend to show rhizoidal tufts at the stem base, but<br />
not on the elongating distal stem <strong>re</strong>gion. When the stem<br />
is as well-developed as it is in the variety densa, the<br />
proximal rhizoids have been lost in the soil or by<br />
crowded leaves and most <strong>of</strong> the stem appears non<br />
tomentose.<br />
North American <strong>re</strong>ports <strong>of</strong> plants to now<br />
designated as Tortella inclinata have not derived from<br />
the kinds <strong>of</strong> habitats whe<strong>re</strong> T. densa in Europe is known
to grow. With the addition to American herbaria <strong>of</strong><br />
<strong>re</strong>cent collections in mo<strong>re</strong> northern or upland stations in<br />
Canada and Alaska, a mo<strong>re</strong> complete range <strong>of</strong> variation<br />
was made available for analysis.<br />
The decision was made to associate Tortella<br />
densa with T. inclinata as a variety after the discovery<br />
that their ranges in North America overlapped<br />
intimately as did their morphological characteristics,<br />
leaving the var. inclinata as an ecological variant that is<br />
somewhat depauperate compa<strong>re</strong>d to the morphological<br />
complexity <strong>of</strong> var. densa, the former variety with the<br />
natu<strong>re</strong> <strong>of</strong> a <strong>re</strong>cent colonizer <strong>of</strong> <strong>re</strong>latively new substrates.<br />
While examining inland stations <strong>of</strong><br />
Netherlands <strong>re</strong>ports <strong>of</strong> Tortella flavovi<strong>re</strong>ns (all proving<br />
to be T. inclinata), Rubers (1973) made the inte<strong>re</strong>sting<br />
observation that he found plants with acuminate apices,<br />
so that they strongly <strong>re</strong>sembled those <strong>of</strong> T. densa. He<br />
dismissed their identity because the habit <strong>of</strong> the<br />
specimen did not <strong>re</strong>semble that <strong>of</strong> the latter species and<br />
suggested that the form <strong>of</strong> the leaf tip <strong>of</strong> T. inclinata<br />
varied with variation in ecological circumstances. He<br />
suggested that it was due to acuminate leaf tips that the<br />
two species have been very difficult to identify. It is<br />
suggested in the p<strong>re</strong>sent paper that both taxa a<strong>re</strong> variants<br />
<strong>of</strong> T. inclinata.<br />
One important specimen that helps to <strong>re</strong>veal an<br />
amplified eastern distribution <strong>of</strong> var. densa is the<br />
following, cited by Crum and Anderson (1981: 308)<br />
under Tortella inclinata: USA, Vermont, Equinox Mtn.<br />
(Bennington Co.), rocks, William Randolph Taylor<br />
155a, 9.18.22 (MICH). The authors write "habitat<br />
unknown" although the substrate is given on the label at<br />
MICH, and it is "rock." The specimen is frustrating in<br />
two aspects: it does not show leaves that a<strong>re</strong> cucullate,<br />
as the authors emphasize for the species, but a<strong>re</strong><br />
narrowly acute to acuminate. It did not even grow in a<br />
valley bottom whe<strong>re</strong> one might hope to find some kind<br />
<strong>of</strong> alluvium (Equinox Mt. attains 3816 ft., or around<br />
1000 m). Yet the specimens a<strong>re</strong> undoubtedly <strong>re</strong>lated to<br />
T. inclinata s.l. but they we<strong>re</strong> also undoubtedly on a<br />
mountain and on rock. They a<strong>re</strong>, in fact, T. inclinata<br />
var. densa. This station suggests that the variety may<br />
occur elsewhe<strong>re</strong> in the Appalachian Mountains in<br />
eastern North America.<br />
C. Müller and Kindberg's description <strong>of</strong><br />
Tortella inclinatula (Macoun & Kindberg 1892)<br />
<strong>re</strong>p<strong>re</strong>sents one ext<strong>re</strong>me <strong>of</strong> the variability <strong>of</strong> T. inclinata<br />
s.l. in North America. The stems we<strong>re</strong> very small, only<br />
0.5 cm, and had no branches. The leaves we<strong>re</strong> cucullate,<br />
the costa was yellow and pellucid, the capsule "narrowcylindric,<br />
nearly straight, sube<strong>re</strong>ct," unlike the strongly<br />
inclined capsules <strong>of</strong> European T. inclinata, the<br />
description taken from fruiting material from the<br />
alluvium <strong>of</strong> abandoned river channels.<br />
Inez Haring's (1938) description <strong>of</strong> To<strong>re</strong>lla<br />
inclinata included mo<strong>re</strong> specimens and mo<strong>re</strong> characters,<br />
and one can begin to see elements diverging from the<br />
var. inclinata: the stems attained 1 cm, the leaves we<strong>re</strong><br />
long, to 5 mm, "sublinear to ovate-lanceolate, usually<br />
narrowing abruptly to a point" but also "sometimes to an<br />
37<br />
acuminate apex" which is "usually cucullate." The<br />
costa is yellow, but "may be <strong>re</strong>d at the base in matu<strong>re</strong><br />
leaves." The walls we<strong>re</strong> thick, "giving a honey-comb<br />
appearance to the cells...." Seville Flower's<br />
accompanying illustration shows attenuate leaf apices,<br />
although if they <strong>re</strong>p<strong>re</strong>sent leaves from a perichaetiate<br />
plant, the cucullate apices might be difficult to draw<br />
distinctively, as they a<strong>re</strong> in sterile stems <strong>of</strong> var.<br />
inclinata.<br />
Appearing in her description a<strong>re</strong> elements <strong>of</strong><br />
the variety densa postulated he<strong>re</strong>: the long stems, the<br />
longer leaves (to 5 mm) that a<strong>re</strong> acuminate and not<br />
cucullate, although they a<strong>re</strong> concave (tubulose), the<br />
tendency toward color, the thick walls obscuring the<br />
a<strong>re</strong>olation. The low and fewer papillae might <strong>re</strong>fer to the<br />
<strong>re</strong>duction to the papillae at the expense <strong>of</strong> thicker<br />
superficial walls.<br />
American material shows the thick superficial<br />
walls clearly as well as cucullation at the leaf apex. This<br />
thickened wall tendency <strong>of</strong> the species is seen in the<br />
<strong>re</strong>latively thick-walled proximal cells, at least in the<br />
proximal a<strong>re</strong>a distal to the leaf insertion. The high<br />
papillae and dense walls seem to have a similar<br />
function: to buffer the interior cell. The walls can be<br />
thick and nearly smooth, thick and highly papillose or<br />
only dense with tall, solid papillae. The papillae a<strong>re</strong><br />
solid (not hollow), as though they we<strong>re</strong> a spongy cell<br />
wall, or to make the a<strong>re</strong>a porous to water and gas<br />
exchange and still protect the cell from ext<strong>re</strong>me<br />
environmental conditions. This is <strong>re</strong>miniscent also <strong>of</strong> T.<br />
tortuosa var. arctica in which the laminal papillae seem<br />
to become <strong>re</strong>duced with inc<strong>re</strong>ase in cell wall thickness.<br />
Both taxa may have smooth c<strong>re</strong>nulate rather than<br />
papillose c<strong>re</strong>nulate marginal cells. That var. densa<br />
occurs most f<strong>re</strong>quently in rocky cliffs, one might<br />
speculate that the c<strong>re</strong>vices <strong>of</strong> the rocks themselves<br />
provide similar protection necessary to the species, as<br />
per the discussion <strong>of</strong> Stee<strong>re</strong> (1976) above.<br />
Tortella inclinata var. inclinata has a cross<br />
section showing an unistratose lamina adjacent to the<br />
nearly circular costa with walls that a<strong>re</strong> not thick, and<br />
papillae that a<strong>re</strong> sharply delineated. The var. densa<br />
differs by <strong>of</strong>ten being bistratose juxtacostally and with a<br />
lunate costa, f<strong>re</strong>quently adaxially concave, the papillae<br />
on both surfaces collectively as thick as the lumen in<br />
cross section and tapering to the margin which <strong>of</strong>ten has<br />
a smaller, thin-walled smooth cell consistent with the<br />
tendency <strong>of</strong> the taxon to occasionally display a marginal<br />
border <strong>of</strong> smooth, short-<strong>re</strong>ctangular cells. Except for the<br />
thicker superficial walls and prominent papillae, the<br />
cross section <strong>of</strong> the leaf strongly <strong>re</strong>sembles that <strong>of</strong> T.<br />
rigens.<br />
If one postulates that Tortella inclinata var.<br />
inclinata is a small, lowland form, perhaps numerous<br />
other closely <strong>re</strong>lated taxa may sha<strong>re</strong> a similar<br />
morphological variation <strong>re</strong>lated to elevation: short,<br />
blunt-leaved forms <strong>re</strong>-colonizing lowland stations once<br />
blocked by glacial ice or melt water and whe<strong>re</strong> fruiting<br />
occurs, whe<strong>re</strong>as long-leaved variants occur in the<br />
uplands. Plerurochaete luteola (Besch.) Thér., for
example in the United States is a highland plant, P.<br />
squarrosa (Brid.) Lindb. mo<strong>re</strong> <strong>of</strong> a lowland plant (both<br />
a<strong>re</strong> p<strong>re</strong>sently conside<strong>re</strong>d synonymous). Anoectangium<br />
peckii (Sull. ex Peck) Sull. ex Aust. a highland, A.<br />
aestivum (Hedw.) Mitt. a lowland plant (both also<br />
conside<strong>re</strong>d synonymous).<br />
The stems <strong>of</strong> North American plants produce<br />
lateral axes or shoots on which primordial leaves a<strong>re</strong><br />
distributed at distant intervals, becoming mo<strong>re</strong> crowded<br />
at the apex. These shoots develop longer leaves, and on<br />
some stems may be detached at which time they<br />
<strong>re</strong>semble fully grown leafy stems with rhizoids. Note<br />
that Limpricht's (1890, p.603) illustration <strong>of</strong> Tortella<br />
inclinata shows a small branch arising laterally from the<br />
main stem in a manner rather similar to what is<br />
described he<strong>re</strong>. Possibly the plants <strong>re</strong>produce asexually<br />
in this way. Coarse rhizoids a<strong>re</strong> p<strong>re</strong>sent along matu<strong>re</strong><br />
stems. Also the stems a<strong>re</strong> fragile and disarticulate in<br />
whorls. These whorls may or may not <strong>re</strong>p<strong>re</strong>sent annual<br />
growth, but, as in the whorled branches <strong>of</strong> Tortella<br />
humilis, simply that the leaves a<strong>re</strong> mo<strong>re</strong> obviously<br />
arranged in verticels densely distributed on the stem.<br />
One could imagine the turf expanding by a<br />
kind <strong>of</strong> branch-budding process in <strong>re</strong>latively loosely<br />
consolidated sediments <strong>of</strong> a large clast size, such as<br />
sand, <strong>re</strong>lative to silt or clay. The fully grown shoot<br />
would be less likely to be buried in loose sand than<br />
other vegetative structu<strong>re</strong>s, such as bulbils, gemmae and<br />
leaf fragments. Other species <strong>of</strong> sandy habitats may<br />
<strong>re</strong>produce this way, but without obvious shoots as in<br />
Tortella densa. Possibilities may include branched,<br />
highly tomentose or radiculose weedy species <strong>of</strong><br />
Bryum, such as B. pallescens Schleich. ex Schwaegr. or<br />
Bryum caespiticium Hedw. It is <strong>of</strong>ten difficult in dense<br />
mats <strong>of</strong> these species to tell whether one has a branch or<br />
a fully formed plant. Note again that, at least in Europe,<br />
T. inclinata is said to generate deciduous shoots at the<br />
stem apex (Crundwell & Nyholm 1962; Smith 1978;<br />
Nyholm 1989).<br />
The populations in the American and Canadian<br />
West also develop stems <strong>of</strong> a significantly mo<strong>re</strong> gracile<br />
appearance alongside robust stems in or beside matu<strong>re</strong><br />
clumps, and perhaps these mo<strong>re</strong> delicate plants<br />
<strong>re</strong>p<strong>re</strong>sent matu<strong>re</strong>d lateral stem shoots. Apical segments<br />
<strong>of</strong> the stem composed <strong>of</strong> similarly gracile leaves that a<strong>re</strong><br />
distinct from the broader and longer leaves lower on the<br />
stem a<strong>re</strong> also visible in some stems, as a<strong>re</strong> what appear<br />
to be densely foliose side branches composed <strong>of</strong> axes on<br />
which narrower leaves occur and which may be fully<br />
matu<strong>re</strong> lateral shoots. Most Tortella species develop<br />
larger leaves near the stem apex, giving the habit a club<br />
shape. In Tortella densa the leaves a<strong>re</strong> generally not<br />
enlarged at the stem apex in this way, perhaps to<br />
accommodate dispersal mechanisms involving the lower<br />
stem.<br />
In other species <strong>of</strong> Tortella, the unfertilized<br />
perichaetia a<strong>re</strong> usually conspicuous at the stem apex,<br />
especially in species with diffe<strong>re</strong>ntiated perichaetial<br />
leaves such as T. tortuosa, T. fragilis and T. inclinata. In<br />
the few perichaetiate stems seen <strong>of</strong> T. densa in North<br />
38<br />
America, the perichaetia we<strong>re</strong> not at the turf surface<br />
but along the lower stem, persisting from their initial<br />
apical development.<br />
As discussed above under Tortella inclinata<br />
var. inclinata, the striking perichaetial leaves <strong>of</strong> fruiting<br />
specimens cannot be compa<strong>re</strong>d because var. densa is<br />
not known to fruit. Little diffe<strong>re</strong>nce could be found<br />
between perichaetia <strong>of</strong> unfertilized archegonia <strong>of</strong> both<br />
varieties.<br />
While many species <strong>of</strong> the genus Tortella may<br />
disperse through leaf fragmentation, T. densa, upon<br />
further study <strong>of</strong> additional specimens and populations in<br />
the field, may be found to disperse instead through stem<br />
modifications. Why var. densa does not fruit in North<br />
America is a mystery because both perigoniate and<br />
perichaetiate populations exist, occasionally in<br />
contiguity. The var. inclinata <strong>of</strong> mo<strong>re</strong> moderate<br />
ecological <strong>re</strong>gimes, however, does fruit.<br />
Tortella inclinata s.l. might once have had a<br />
range that extended into a<strong>re</strong>as whe<strong>re</strong> fertilization was<br />
successful (dependent on an environmental condition<br />
such as temperatu<strong>re</strong>). When this condition was lost,<br />
vegetative propagation such as fragmentation became<br />
important for dispersal. This perhaps enabled the plants<br />
to (<strong>re</strong>)colonize a<strong>re</strong>as once under water and fruiting was<br />
again possible: the alvars, limestone a<strong>re</strong>as with thin to<br />
absent soil and historically newly exposed substrates in<br />
temperate <strong>re</strong>gions.<br />
This possibility may also be suggested for<br />
Tortella alpicola which fragments in the highlands and<br />
is fertile (perichaetiate) in lower elevations.<br />
Tortella inclinata var. densa, according to<br />
European specimens from S and NY determined by<br />
Albertson, Crundwell and Nyholm, when it is found on<br />
alvar, is <strong>re</strong>duced in the exp<strong>re</strong>ssion <strong>of</strong> its characteristics:<br />
while many leaves on a stem a<strong>re</strong> narrowly acute, many<br />
others a<strong>re</strong> decidedly cucullate. The hyaline proximal<br />
cells <strong>of</strong> plants from this habitat also become peculiar in<br />
that they intergrade on many <strong>of</strong> the leaves, or the<br />
proximal hyaline <strong>re</strong>gion is <strong>re</strong>ctangular (not V-shaped),<br />
but a<strong>re</strong> in some leaves strongly diffe<strong>re</strong>ntiated in a Vshape<br />
in leaves from the same stem. The stems may also<br />
be strongly <strong>re</strong>flexed or squarrose-<strong>re</strong>curved. The cells a<strong>re</strong><br />
larger and the walls thicker than in robust specimens<br />
from upland stations. Plants from alvar vegetation in the<br />
G<strong>re</strong>at Lakes <strong>re</strong>gion may display similar characteristics,<br />
but so far, similar plants from these a<strong>re</strong>as a<strong>re</strong> T. rigens<br />
only.<br />
At the other ext<strong>re</strong>me, in Europe, a specimen<br />
(England: Westmo<strong>re</strong>land Co., limestone rocks on<br />
northwest side <strong>of</strong> Beacon Hill, Orton, 19/3/1961, 1200<br />
ft. (400 m), A. C. Crundwell, NY) was <strong>of</strong> a fuscous to<br />
black coloration, long leaves (to 3.5) on <strong>re</strong>latively short<br />
stems (1 cm) with thick superficial laminal walls,<br />
bistratose juxtacostally in the midleaf <strong>re</strong>gion. The leaf<br />
shape strongly <strong>re</strong>sembles those <strong>of</strong> Tortella tortuosa var.<br />
arctica, being rather abruptly contracted just above the<br />
hyaline proximal cells into a straight, somewhat rigid<br />
limb, the laminae evenly tape<strong>re</strong>d to and confluent with a<br />
quite long, multicellular mucro <strong>of</strong> 2–6 elongate, smooth
cells. Another robust specimen from I<strong>re</strong>land (East<br />
Mayo, E. Hegewald 2632, NY) with similar<br />
characteristics also shows little tomentum, or this very<br />
sparse along the stem. In both specimens the leaves did<br />
not detach as easily into whorls or whorled fascicles as<br />
in the American material examined.<br />
In Japan, Saito (1975) described montane<br />
specimens <strong>of</strong> Tortella tortuosa that strongly <strong>re</strong>sembled<br />
T. inclinata. The specimens had "costae whose adaxial<br />
surface cells a<strong>re</strong> much elongated and smooth, forming a<br />
sharp b<strong>re</strong>ak in the a<strong>re</strong>olation <strong>of</strong> lamina." He indicated<br />
that these plant had "apical portions" being "not involute<br />
and gradually narrowed into an attenuate apex. In<br />
addition, the stems <strong>of</strong> these plants a<strong>re</strong> rather long (10–<br />
20 mm long) and the rhizoids a<strong>re</strong> developed from the<br />
upper portion <strong>of</strong> the stem." Some aspects <strong>of</strong> this<br />
description <strong>re</strong>semble characteristics <strong>of</strong> T. inclinata var.<br />
densa (the upland (non-alluvial) habitat and the long<br />
stem in addition to the smooth, elongate cells <strong>of</strong> the<br />
adaxial costal surface).<br />
Short-mucronate, sterile forms <strong>of</strong> Encalypta<br />
Hedw. may be confused with T. densa: they a<strong>re</strong> <strong>re</strong>ddishg<strong>re</strong>en,<br />
tubulose with a proximal cell <strong>re</strong>gion similar to<br />
those forms <strong>of</strong> T. densa whe<strong>re</strong> the proximal V-shape is<br />
not strong. Encalypta species a<strong>re</strong> immediately<br />
diffe<strong>re</strong>ntiated by the quadrate, papillose cells on the<br />
adaxial surface <strong>of</strong> the costa and the distinctive thickened<br />
cross-walls in contrast to thin vertical walls <strong>of</strong> the<br />
hyaline proximal cells. Encalypta procera Bruch<br />
usually is accompanied by brown filiform brood bodies.<br />
A collection from Emmet Co., Michigan<br />
(I<strong>re</strong>land 4362, CANM) was first thought to contain both<br />
T. tortuosa and T. inclinata in mixtu<strong>re</strong>, but actually the<br />
plants <strong>re</strong>p<strong>re</strong>sented one variable collection with leaf cells<br />
up to and exceeding 14 µm. Smaller plants in the<br />
collection <strong>re</strong>sembled T. humilis in their very broad<br />
leaves, flat cross-section and the <strong>re</strong>flexed mucro, rather<br />
than inflexed mucro typical <strong>of</strong> other collections and <strong>of</strong><br />
most leaves in this collection. This collection was also,<br />
according to the label, anomalously growing "On sandy<br />
soil near lake." The leaves we<strong>re</strong> not rigidly e<strong>re</strong>ct.<br />
British Columbia: foot <strong>of</strong> Mabel Mountain,<br />
1300 ft. (400 m), on sand in river (with T. tortuosa)<br />
Aug. 24, 1950 V. J. Krajina (UBC)—this specimen<br />
shows the clea<strong>re</strong>st <strong>re</strong>lationship to T. inclinata var.<br />
mutica Latzel (see discussion above under var.<br />
inclinata). The leaves <strong>of</strong> the proximal whorl a<strong>re</strong> very<br />
short (2:1) and fistulose, <strong>re</strong>sembling the leaf <strong>of</strong> Aloina.<br />
The costa in the lowermost leaves also disappears<br />
befo<strong>re</strong> the apex. In succeeding whorls, however, the leaf<br />
elongates, is successively less fistulose, finally deeply<br />
cucullate with an excur<strong>re</strong>nt costa. The Wisconsin<br />
material was var. inclinata, the BC material he<strong>re</strong> var.<br />
densa: massive superficial cell walls (pedestaled<br />
papillae). The leaves we<strong>re</strong> brick <strong>re</strong>d, as was the T.<br />
tortuosa growing intermixed (distinguished by the<br />
quadrate papillose cells on the ventral surface <strong>of</strong> the<br />
costae and the long mucro, the narrowly acute apex and<br />
dense tomentum throughout the stem).<br />
39<br />
In Europe, the opposite ext<strong>re</strong>me, and one to<br />
be anticipated in North America, may be <strong>re</strong>p<strong>re</strong>sented<br />
by: Scotland, on limestone rock, alt. 2000 ft. (606 m),<br />
Wallace s.n. June 30, 1963 (NY), with cell sizes very<br />
small, costa highly colo<strong>re</strong>d brown-orange. Yet in the<br />
youngest leaves (these a<strong>re</strong> large) they a<strong>re</strong> pale g<strong>re</strong>en, as<br />
one might expect—with very large stems. These a<strong>re</strong><br />
very acuminate but one can easily see they can become<br />
cucullate when the leaves a<strong>re</strong> <strong>re</strong>duced. No tomentum<br />
was found on European stems examined.<br />
A specimen originally identified as Tortella<br />
tortuosa from southern Wisconsin was at first thought<br />
he<strong>re</strong> to be T. inclinata, yet it occur<strong>re</strong>d in disturbed soil<br />
on an exposed hillside, associated with a fen and oak<br />
opening (Christy 4272 UBC)—an atypical substrate and<br />
habitat. The subcucullate, obtuse leaf apices, and naked<br />
adaxial surface <strong>of</strong> the costa p<strong>re</strong>cluded it from being T.<br />
tortuosa, yet many <strong>of</strong> the leaves we<strong>re</strong> very narrow<br />
throughout the leaf and into the apex, the leaf cells only<br />
came to 10 µm (not 12 µm as in T. inclinata. The<br />
pedestaled papillae we<strong>re</strong> diagnostic. Although the<br />
leaves seemed yellowish, their orange coloration was<br />
brought out after soaking in dilute KOH.<br />
Specimens examined:<br />
B.C.: above Muncho Lake, Alaska Highway mile 465,<br />
rock slide. Aug. 26, 1967, F. M. Boas 67032<br />
(UBC).<br />
B.C.: Range Lake, N.E. <strong>of</strong> Tweedsmuir Glacier, damp<br />
c<strong>re</strong>vices <strong>of</strong> cliff, 1100 m., 59–52°N, 137–<br />
50°W, July 26, 1992, Sch<strong>of</strong>ield, Godf<strong>re</strong>y &<br />
Goward 98203 (UBC).<br />
B.C.: Mt. Stalin A<strong>re</strong>a, Tuchodi Lakes, W Lake; near SE<br />
end <strong>of</strong> Lake on S sho<strong>re</strong>. 58°12'N, 124°31'W,<br />
934 m, on steep, seepy calca<strong>re</strong>ous cliffs on<br />
rock faces, on ledges and in c<strong>re</strong>vices, and in<br />
adjacent Picea glauca-Alnus mesic fo<strong>re</strong>st with<br />
wefts <strong>of</strong> Thuidium, Hylocomium and Entodon<br />
concinnus July 25, 1977, D. H. Vitt 19794<br />
(BUF).<br />
N.W.T.: Mackenzie District: alpine Dryas integrifolia,<br />
Cetraria tilesii, Potentilla community, Nahanni<br />
National Park, 61°16'N, 124°12'W; 1200 m, 16<br />
July 1976, S. Talbot T 6077–18 (NY) (as T.<br />
inclinata); Mackenzie District: Logan Mtns,<br />
lake close to S. Nahanni River, 1560 m.,<br />
62°34'N, 128°31'W; on earth slopes at cliff<br />
base, Aug. 15, 1978, Sch<strong>of</strong>ield, Vitt & Horton<br />
70886 (UBC).<br />
Alaska: among pebbles on high gravel banks <strong>of</strong> river<br />
north <strong>of</strong> Wiseman, 28 June 1949, Louis H.<br />
Jordal 2050 (as Tortella tortuosa) (CANM).<br />
Alaska: Ambler River Region, upper Ambler River,<br />
unnamed peak N. <strong>of</strong> "Carnes C<strong>re</strong>ek" near its<br />
junction with Ambler River; ca. 4 miles S. <strong>of</strong><br />
mouth <strong>of</strong> Ulaneak C<strong>re</strong>ek; ca. 67°20'N,<br />
156°51'W, dry calca<strong>re</strong>ous ridge, 1600 ft. (490<br />
m), 6 July 1976, M. Lewis 1768 (NY, F)<br />
(perigoniate plants).
Mich.: Emmet Co., on sandy soil near lake, Sturgeon<br />
Bay, Wilderness State Park, July 26, 1961, R.<br />
R. I<strong>re</strong>land 4362 (CANM) (<strong>re</strong>sembles T.<br />
tortuosa in habit).<br />
Wisc.: Waukesha Co.: Genesee Oak Opening and Fen<br />
Scientific A<strong>re</strong>a, 1.6 km W <strong>of</strong> Genesee T6N,<br />
R18E, NE 1/4 SW 1/4 S28 (fen), SW 1/4 NE<br />
1/4 S28 (oak opening), 280–290 m, on<br />
disturbed soil <strong>of</strong> exposed hillside, oak opening,<br />
full exposu<strong>re</strong>, with Euphorbia corollata, Stipa,<br />
Cladonia, July 9, 1982, J. A. Christy 4272<br />
(UBC).<br />
7. TORTELLA RIGENS Plate 8 (fig. 11–13) & 9<br />
Tortella rigens N. Alberts., Act. Phytogeogr. Suec. 20:<br />
197. 15, 16. 1946.<br />
Plants firm, somewhat rigid, occasionally brittle when<br />
dry, in low, dense, dark brown to black to emeraldg<strong>re</strong>en<br />
tufts, compact, elongate, not rosulate. Stem 1–3<br />
cm, ra<strong>re</strong>ly to 4 cm high, usually branched, densely<br />
foliose, leaf bases not evident between the leaves,<br />
central strand absent, tomentum rufous, dense, visible<br />
between the leaf bases especially along the lower stem.<br />
Stem leaves firm, somewhat rigid, stiffly e<strong>re</strong>ct,<br />
especially proximal leaves, to loosely twisted and<br />
moderately contorted when dry, e<strong>re</strong>ct and somewhat<br />
sp<strong>re</strong>ading when moist, gradually larger and mo<strong>re</strong><br />
crowded toward the stem tips, distal-most leaves usually<br />
mo<strong>re</strong> sp<strong>re</strong>ading than the e<strong>re</strong>ct leaves or leaf bases<br />
below; leaf shape variable within clumps and on the<br />
same stem: short stems with leaves short, ovatelanceolate,<br />
margins inwardly tapering to acute apices,<br />
longer stems with longer, mo<strong>re</strong> narrowly lanceolate<br />
leaves with mo<strong>re</strong> acuminate apices, the proximal leaves<br />
f<strong>re</strong>quently narrowly lanceolate, distal leaves ovate or<br />
broadly ovate-lanceolate, generally narrowing<br />
gradually, but <strong>of</strong>ten some distal-most leaves with an<br />
abrupt narrowing with parallel sides in the distal<br />
quarter, leaf tips fragile, the older ones usually eroded;<br />
deeply concave to canaliculate-tubulose in longer<br />
leaves, 1.5–3(–4) mm long; base undiffe<strong>re</strong>ntiated in<br />
shape to broadly ovate below a gradually to abruptly<br />
lanceolate distal lamina; margins variously plane, e<strong>re</strong>ct,<br />
to incurved, inf<strong>re</strong>quently undulate in some leaves, apex<br />
fragile, acute to acuminate, abruptly ending befo<strong>re</strong> a<br />
sharp apiculus or narrowly acute and confluent with a<br />
conical, nearly mucronate apiculus; in shorter leaves<br />
naviculate to nearly cucullate, distinctly cucullate in the<br />
awl-shaped youngest leaves arising from the stem apex;<br />
longer, narrow leaves with e<strong>re</strong>ct to broadly incurved<br />
margins extending to the leaf apex; costa shortexcur<strong>re</strong>nt<br />
into a sharp, narrow, denticulate or smoothly<br />
conical mucro <strong>of</strong> 1–5(–10) cells, adaxial surface<br />
cove<strong>re</strong>d by quadrate, papillose laminal cells except for a<br />
narrow groove <strong>of</strong> elongate (8:1) smooth cells<br />
continuous throughout length <strong>of</strong> the leaf, in cross<br />
section, adaxial epidermal cells interrupted in the center,<br />
exposing the adaxial ste<strong>re</strong>id layer by about two cells,<br />
40<br />
adaxial and abaxial ste<strong>re</strong>id bands p<strong>re</strong>sent throughout,<br />
guide cells p<strong>re</strong>sent in one row; proximal laminal cells<br />
abruptly diffe<strong>re</strong>ntiated from distal cells, lacking a zone<br />
<strong>of</strong> cells intermediate in color, cell size, and papillosity,<br />
yellow-hyaline, elongate, 6–8:1, firm to laxly thinwalled,<br />
smooth; marginal angle <strong>of</strong> diffe<strong>re</strong>ntiated cells<br />
steep due to the quadrate laminal cells extending<br />
juxtacostally far down into the proximal cell <strong>re</strong>gion,<br />
with a marginal row <strong>of</strong> firm to thin-walled, quadrate to<br />
short-<strong>re</strong>ctangular smooth cells extending a short way up<br />
the lamina or to mid-leaf; distal laminal cells<br />
f<strong>re</strong>quently bistratose on one or both laminae<br />
juxtacostally or extending marginward as one to two<br />
pairs <strong>of</strong> cells, but never extending to the margins even<br />
in longer leaves with narrowed apices, cells gradually<br />
smaller toward the margins; rounded-quadrate or<br />
hexagonal, with slightly thickened walls, (12–)14(–17)<br />
µm wide, strongly papillose, a<strong>re</strong>olation mo<strong>re</strong> or less<br />
distinct, diffe<strong>re</strong>ntiated distal marginal cells absent<br />
except in longer leaves possessing a somewhat<br />
diffe<strong>re</strong>ntiated and deciduous apex, these having obscu<strong>re</strong><br />
(due to erosion) to distinct thicker-walled, less papillose<br />
to smooth, elongate marginal cells. Asexual<br />
<strong>re</strong>production: vegetative propagation appa<strong>re</strong>ntly by<br />
means <strong>of</strong> fragile leaf tips in the longer leaves. Sexual<br />
condition: appa<strong>re</strong>ntly dioicous: only sterile and<br />
perichaetiate plants seen. Perichaetia terminal, leaves<br />
long-lanceolate, costa excur<strong>re</strong>nt into a long awn or<br />
subula. Sporophytes: unknown.<br />
Forming shag-like patches on limestone alvar<br />
pavement (but not limestone bluffs, boulders and other<br />
calca<strong>re</strong>ous landforms), mostly near sea level (to 100 m).<br />
In North America: Ont.; Mich., N.Y., Ohio. Distributed<br />
in the Baltic <strong>re</strong>gion <strong>of</strong> Sweden whe<strong>re</strong> it is conside<strong>re</strong>d<br />
ra<strong>re</strong> (Nyholm 1989), the Baltic <strong>re</strong>publics <strong>of</strong> the former<br />
U.S.S.R. (Ignatov & Afonina 1992), with one <strong>re</strong>port <strong>of</strong> a<br />
specimen seen from Czechoslovakia (Düll 1984). Pilous<br />
(1965) has <strong>re</strong>ported numerous collections in<br />
Czechoslovakia.<br />
Herbaria examined: BUF, CANM, DUKE,<br />
MICH, NY, S, UBC.<br />
The species is confined to temperate climate<br />
<strong>re</strong>gimes on limestone, particularly in alvar pavements,<br />
rather than in colder austral or bo<strong>re</strong>al a<strong>re</strong>as and their<br />
altitudinal equivalents as has been indicated on some<br />
misdetermined specimens from the Rocky Mountains.<br />
So far, it is only known in Europe from the alvars <strong>of</strong> the<br />
circum-Baltic states and Czechoslovakia and may be<br />
expected in other a<strong>re</strong>as with appropriate landforms.<br />
Braunmiller et al. (1971) doubted that the species was<br />
endemic to Scandinavia and Czeckoslovakia and<br />
anticipated its discovery in central Europe. By 1989,<br />
however, it has not been discove<strong>re</strong>d in Germany (Düll<br />
& Meinunger 1989), or other a<strong>re</strong>as in Europe.<br />
In North America, alvars appear confined to<br />
substrates <strong>of</strong> Ordovician and Silurian limestones and<br />
dolomites, being a<strong>re</strong>as <strong>of</strong> exposed rock adjacent to<br />
bodies <strong>of</strong> water. These a<strong>re</strong>as we<strong>re</strong> once under water<br />
when sea and inland water levels we<strong>re</strong> higher. The<br />
exposu<strong>re</strong>s occur around the G<strong>re</strong>at Lakes and St.
Law<strong>re</strong>nce River and associated lakes, such as Lake<br />
Simcoe in Ontario, Canada and Lake Champlain in the<br />
states <strong>of</strong> New York and Vermont. These a<strong>re</strong>as may be<br />
expected to harbor mo<strong>re</strong> populations <strong>of</strong> this species (see<br />
Catling & Brownell 1995 for the distribution <strong>of</strong> the<br />
alvars in the G<strong>re</strong>at Lakes Region).<br />
Since these two continental <strong>re</strong>gions a<strong>re</strong> most<br />
likely to have a similar post-glacial history and<br />
geomorphology, details on the distribution and substrate<br />
<strong>of</strong> the triad <strong>of</strong> closely <strong>re</strong>lated taxa, Tortella inclinata<br />
var. densa, T. inclinata var. inclinata and T. rigens, may<br />
contribute to an understanding <strong>of</strong> the <strong>re</strong>lationship <strong>of</strong><br />
their biogeography and evolution. Tortella inclinata var.<br />
densa, in montane and bo<strong>re</strong>al situations in Europe and<br />
in the North American west, occupies the most<br />
potentially stable <strong>of</strong> the th<strong>re</strong>e habitats associated with<br />
these taxa, and it may have been the most likely to find<br />
a <strong>re</strong>fugium during glacial periods. The distribution <strong>of</strong> T.<br />
inclinata may <strong>re</strong>flect the availability <strong>of</strong> <strong>re</strong>cently<br />
stabilized habitats in temperate situations. Alvars have a<br />
mo<strong>re</strong> <strong>re</strong>stricted distribution as does T. rigens, which is<br />
appa<strong>re</strong>ntly confined to it.<br />
Alvar, it should be stated, is not a geological<br />
term but an ecological one: "the plant community<br />
consisting typically <strong>of</strong> mosses and calciphilous<br />
herbaceous plants that grows on steppelike shallow<br />
alkaline soils overlying Scandinavian limestones" (it is a<br />
Swedish word: Ålvar; Gove et al. 1976). Alvar is<br />
distinct from the geological term karst which <strong>re</strong>lates to<br />
subsurface conditions and is "a limestone <strong>re</strong>gion marked<br />
by sinks, abrupt ridges, ir<strong>re</strong>gular protuberant rocks,<br />
caverns, and underground st<strong>re</strong>ams" (Gove et al. 1976).<br />
In North America the<strong>re</strong> a<strong>re</strong> karst <strong>re</strong>gions in New<br />
Mexico and Kentucky and in Europe the<strong>re</strong> a<strong>re</strong> the karst<br />
<strong>re</strong>gions <strong>of</strong> the Dalmatian coast in the Mediterranean, but<br />
the surficial deposition <strong>of</strong> sediment is appa<strong>re</strong>ntly deep<br />
enough to p<strong>re</strong>clude them from supporting an alvar<br />
vegetation. A<strong>re</strong>as stripped <strong>of</strong> topsoil a<strong>re</strong> associated with<br />
a<strong>re</strong>as once glaciated or <strong>re</strong>cently underwater, especially<br />
in northern latitudes. Plants <strong>of</strong> alvars do not necessarily<br />
match those <strong>of</strong> karst <strong>re</strong>gions, which a<strong>re</strong> most<br />
<strong>re</strong>p<strong>re</strong>sented in warm subtemperate to subtropical<br />
latitudes.<br />
Of the numerous alvar vegetation types<br />
delineated by Catling and Brownell (1995), only in the<br />
"Pavements and Pavement Edges" type a<strong>re</strong> bryophytes<br />
mentioned: Riccia sorocarpa Bisch. for a<strong>re</strong>as with some<br />
moistu<strong>re</strong>, and Tortella tortuosa, Tortula ruralis (Hedw.)<br />
Gaertn., Meyer & Scherb., and Ceratodon purpu<strong>re</strong>us<br />
(Hedw.) Brid. on the "drier pavements with a...soil<br />
depth <strong>of</strong> less than 2 cm." See discussion under T. densa<br />
for associated Tortella species in European stations.<br />
The epithet <strong>re</strong>fers to the somewhat rigid<br />
character <strong>of</strong> the leaves (that is, not as rigid as in Tortella<br />
fragilis). The leaves lower on the stem when dry,<br />
however, may be as rigidly e<strong>re</strong>ct and straight as those <strong>of</strong><br />
T. fragilis.<br />
The identification <strong>of</strong> this species for the North<br />
American flora, just as with Tortella inclinata var.<br />
densa discussed above, came about by attempting to<br />
41<br />
<strong>re</strong>concile morphologically anomalous specimens and<br />
substrates <strong>of</strong> traditionally understood Tortella inclinata<br />
with what might be expected from the literatu<strong>re</strong>. The<br />
few specimens <strong>of</strong> T. rigens a<strong>re</strong> scatte<strong>re</strong>d in five North<br />
American herbaria, making it difficult to characterize<br />
American populations, as opposed to the <strong>re</strong>latively<br />
abundant European specimens <strong>re</strong>p<strong>re</strong>sented in Swedish<br />
collections (at S).<br />
Two specimens originally determined as<br />
Tortella tortuosa from Ohio and New York state had<br />
undeniable characteristics <strong>of</strong> T. tortuosa: lanceolate<br />
leaves, margins rather undulate, with rather long<br />
acuminate apices tipped with mucros. However the<br />
leaves had no papillose or quadrate epidermal cells on<br />
the adaxial surface <strong>of</strong> the costa throughout the leaf, and<br />
some <strong>of</strong> the leaf tips had inrolled leaf margins and we<strong>re</strong><br />
cucullate. They we<strong>re</strong> at first <strong>re</strong>named T. inclinata. Inez<br />
Haring's (1938) description <strong>of</strong> that species included<br />
leaves "sublinear to ovate-lanceolate, usually narrowing<br />
abruptly to a point." Seville Flower's accompanying<br />
illustration showed attenuate leaf apices, much like the<br />
Ohio and New York specimens (see t<strong>re</strong>atment above<br />
under T. inclinata var. inclinata).<br />
However, both specimens we<strong>re</strong> not exactly<br />
characteristic <strong>of</strong> that species either. They seemed to<br />
have broader leaves, be g<strong>re</strong>ener, with leaf cell sizes to<br />
14 µm. Perhaps most tellingly, they both occur<strong>re</strong>d on<br />
limestone pavements, the specimen from Ohio growing<br />
with Opuntia and Liatris species—hardly the alluvium<br />
expected with T. inclinata var. inclinata. Williams<br />
(1968) collected a specimen <strong>of</strong> Tortella inclinata from<br />
an appa<strong>re</strong>ntly anomalous substrate in Ontario: "ba<strong>re</strong><br />
open limestone flats in drier locations than Tortella<br />
tortuosa, Carden flats 1185." The anomalous substrate<br />
in the Williams citation was striking and T. inclinata<br />
collected by Williams was searched for in our CANM<br />
loan without <strong>re</strong>sult. However, several other specimens<br />
<strong>of</strong> T. inclinata in that loan we<strong>re</strong> noted as growing on<br />
limestone pavement, rather than alluvium.<br />
Earlier in 1997, A. C. Crundwell (pers. comm.)<br />
suggested that Tortella rigens might be found in the<br />
grasslands <strong>of</strong> central Canada. The above specimens<br />
we<strong>re</strong> examined to see if they fit the concept <strong>of</strong> that<br />
species sensu Nyholm (1989). This, in fact, is what they<br />
turned out to be.<br />
Specimens <strong>of</strong> Tortella inclinata have no<br />
epidermal cells on the adaxial costal surface, the ste<strong>re</strong>id<br />
cells usually exposed by about th<strong>re</strong>e cells. Tortella<br />
rigens is very similar. It may have an adaxial epidermis<br />
in the proximal part <strong>of</strong> the leaf and the adaxial ste<strong>re</strong>id<br />
layer is less exposed (usually by two ste<strong>re</strong>id cells),<br />
hence the<strong>re</strong> is a somewhat mo<strong>re</strong> narrow groove or<br />
channel running the length <strong>of</strong> the leaf. Tortella inclinata<br />
var. inclinata is <strong>re</strong>gularly cucullate whe<strong>re</strong>as T. rigens is<br />
distinctly cucullate usually only in the smallest leaves or<br />
on the smallest stems, or in the first whorl <strong>of</strong> leaves at<br />
the stem base. The leaf apices <strong>of</strong> T. inclinata var.<br />
inclinata may be acute to narrowly so, the distal laminal<br />
cells, however, a<strong>re</strong> only 10–12 µm. In section, the<br />
leaves a<strong>re</strong> not bistratose juxtacostally, the leaves keeled
eside the costa and broadly incurved above. Tortella<br />
rigens has bistratose cells juxtacostally in the median<br />
portion <strong>of</strong> the leaf and the<strong>re</strong>fo<strong>re</strong> the laminae sp<strong>re</strong>ad out<br />
in a broadly concave leaf cross section, the distal cells<br />
14 µm or mo<strong>re</strong> in width.<br />
Although Tortella rigens was not <strong>re</strong>corded as<br />
part <strong>of</strong> the Canadian moss flora by I<strong>re</strong>land et al. (1987),<br />
it does occur in the most <strong>re</strong>cent checklist <strong>of</strong> the mosses<br />
<strong>of</strong> North America north <strong>of</strong> Mexico (Anderson et al.<br />
1990). The species has p<strong>re</strong>viously been <strong>re</strong>ported from<br />
the United States for Colorado by Weber (1973), and<br />
several specimens have been collected by Hermann and<br />
determined as that species. Since all <strong>of</strong> these collections<br />
occur<strong>re</strong>d in the Rocky Mountains far from alvar<br />
substrates, it was felt necessary to examine European<br />
material to clarify the concept <strong>of</strong> the species.<br />
Specimens from Scandinavia <strong>of</strong> Tortella<br />
rigens, including authentic material identified by<br />
Albertson, we<strong>re</strong> loaned to the author from the Museum<br />
<strong>of</strong> Natural History, Stockholm (S). The specimens we<strong>re</strong><br />
compa<strong>re</strong>d with the species description as given by<br />
Nyholm (1989).<br />
R. Zander (pers. comm.) pointed out the<br />
elongate, smooth cells on the apical margins <strong>of</strong> the<br />
leaves <strong>of</strong> some plants <strong>of</strong> Tortella rigens in Swedish<br />
material—but these occur<strong>re</strong>d only on specimens with<br />
long-lanceolate leaves that showed a narrowed <strong>re</strong>gion in<br />
the apex <strong>of</strong> the leaf. Many <strong>re</strong>duced stems with<br />
cor<strong>re</strong>spondingly <strong>re</strong>duced leaves occur in these Öland<br />
and Gotland collections. Larger stems and leaves start to<br />
display an abrupt apical limb, which may be interp<strong>re</strong>ted<br />
as an apical propagulum since these a<strong>re</strong> deciduous. It is<br />
only these apical elements that a<strong>re</strong> fragile. The apical<br />
leaf <strong>re</strong>gions also have elongate smooth clear cells on the<br />
margins and, in fact, together with the stiffly e<strong>re</strong>ct<br />
leaves and tomentose stems, strongly <strong>re</strong>semble T.<br />
fragilis. (Note that these marginal cells a<strong>re</strong> f<strong>re</strong>quently<br />
eroded and not evident, but many samples exist whe<strong>re</strong><br />
they a<strong>re</strong> as distinctive as in T. fragilis.) These<br />
collections include populations with short stems and no<br />
apical diffe<strong>re</strong>ntiation, grading to long stems that a<strong>re</strong><br />
hardly distinguished from the latter species. Smaller<br />
leaves without apical modifications do not appear to be<br />
fragile at the apex.<br />
Tortella inclinata has f<strong>re</strong>quently been<br />
associated with T. fragilis through "intergrading forms"<br />
(Limpricht 1890; Dixon 1924). Tortella rigens was<br />
probably one <strong>of</strong> those forms befo<strong>re</strong> being <strong>re</strong>moved from<br />
the concept <strong>of</strong> T. inclinata. Persson (1947) indicated<br />
that Tortella rigens may have a "hybrid origin in the<br />
Postglacial" since (in Europe) it is morphologically<br />
intermediate between T. fragilis and T. inclinata. The<br />
deciduous apices and marginal cells noted above seem<br />
to substantiate this suggestion.<br />
In the few American specimens available for<br />
study, the apex may become narrowed, but so far no<br />
bordering tendency has been observed in distal portions<br />
<strong>of</strong> the leaf.<br />
Tortella rigens appears to be much mo<strong>re</strong><br />
polymorphic than one might expect from the key and<br />
42<br />
description <strong>of</strong> it given by Nyholm (1989). The<br />
species can <strong>re</strong>semble T. inclinata s.l. in having short<br />
plants with only cucullate leaves. It can <strong>re</strong>semble T.<br />
tortuosa in having lanceolate leaves that a<strong>re</strong> undulate<br />
and tipped with a short mucro. These can have<br />
anomalous leaf cross sections that a<strong>re</strong> not bistratose<br />
juxtacostally but have the large leaf cells. Taller plants<br />
can <strong>re</strong>semble T. fragilis by <strong>re</strong>ason <strong>of</strong> the fragile leaf tips<br />
<strong>of</strong> specimens with elongated leaf apices and overall by a<br />
mo<strong>re</strong> rigid leaf-stance in dry material. The stablest<br />
characters a<strong>re</strong> those that show the affinity with leaves <strong>of</strong><br />
T. inclinata s.l.: particularly the <strong>re</strong>latively naked adaxial<br />
surface <strong>of</strong> the costa, the inrolled to tubulose to cucullate<br />
leaf margins as well as the imp<strong>re</strong>ssion that the proximal<br />
cell <strong>re</strong>gion occupies less <strong>of</strong> the overall a<strong>re</strong>a <strong>of</strong> the leaf.<br />
Definitive characteristics a<strong>re</strong> the larger size <strong>of</strong> the leaves<br />
(than T. inclinata), the bistratose a<strong>re</strong>a beside the costa in<br />
leaf cross-sections <strong>re</strong>sulting in a broadly tubulose<br />
outline, and the alvar substrate. The plants a<strong>re</strong> generally<br />
taller, and <strong>of</strong> a darker g<strong>re</strong>en (less yellow) color.<br />
Specimens noted to date from North America<br />
mo<strong>re</strong> <strong>re</strong>semble the Tortella tortuosa facies in larger size<br />
and leaf characteristics, especially in undulate leaves,<br />
which a<strong>re</strong> not fragile. The leaves a<strong>re</strong> all tubulose,<br />
however, with occasional cucullate or subcucullate leaf<br />
apices, with distinctive cross sections al<strong>re</strong>ad noted<br />
(bistratose juxtacostally with large lumens beside the<br />
costa becoming sharply <strong>re</strong>duced in size toward the<br />
margins). Specimens in herbaria identified from the<br />
American and Canadian west, possibly because <strong>of</strong> an<br />
expectation that the species would <strong>re</strong>semble T. fragilis<br />
based on European material and literatu<strong>re</strong>, we<strong>re</strong> actually<br />
depauperate examples <strong>of</strong> that latter species (discussed<br />
above).<br />
Tortella inclinata is a rather small plant,<br />
occasionally attaining 15 mm in height. Plants that<br />
<strong>re</strong>semble that species, but which a<strong>re</strong> much larger<br />
overall, such as to 25 mm, and which display variable<br />
leaf apices, rather than the uniformly stubby, nearly<br />
fistulose leaves <strong>of</strong> T. inclinata, together with their<br />
association with a limestone pavement substrate, rather<br />
than gravel, sand and silt, a<strong>re</strong> most likely to be T.<br />
rigens.<br />
The observations listed in the above<br />
description <strong>of</strong> the species parallel in many <strong>re</strong>spects the<br />
Latin description <strong>of</strong> the type by Albertson (1946), which<br />
is roughly translated as follows:<br />
"Tufts robust mo<strong>re</strong> or less rigid, 1.5–3, mo<strong>re</strong><br />
ra<strong>re</strong>ly to 5 cm tall composed <strong>of</strong> stems not or little<br />
branched with <strong>re</strong>d-brown radicles loosely scatte<strong>re</strong>d.<br />
Moistened leaves e<strong>re</strong>ct-patent, dry ones strongly<br />
contorted or crisped; in young plants short, lanceolatetriangular<br />
prominently canaliculate, mitriform in the<br />
apex, matu<strong>re</strong> leaves 4–5 mm long (at the most to 6 mm,<br />
in T. inclinata normally 2–3 mm, at most 4 mm long), at<br />
least in the proximal part canaliculate oblonglanceolate,<br />
mo<strong>re</strong> or less elongate in the distal part, yet<br />
not subulate, very <strong>of</strong>ten broken, suddenly contracted.<br />
The nerve strong, in quite matu<strong>re</strong> plants usually <strong>re</strong>dbrown,<br />
in all parts distinctly separated from the cells <strong>of</strong>
the lamina, when dry mo<strong>re</strong> or less shining. Cells <strong>of</strong> the<br />
leaves formed as in T. inclinata, indeed normally<br />
somewhat larger (around 11–14 µm broad) and at least<br />
in the distal part <strong>of</strong> the leaf less papillose.... Margin<br />
lightly (mo<strong>re</strong> lightly than in T. inclinata) c<strong>re</strong>nulated,<br />
<strong>of</strong>ten smooth or provided with a row <strong>of</strong> hyaline<br />
narrowed cells. The <strong>re</strong>st unknown."<br />
Much <strong>of</strong> Albertson's discussion leading up to<br />
the establishment <strong>of</strong> specimens from southern Sweden<br />
as a distinct and new species involved <strong>re</strong>moving<br />
specimens with certain characters from the<br />
circumscription <strong>of</strong> Tortella inclinata in p<strong>re</strong>vious <strong>re</strong>ports<br />
from his study a<strong>re</strong>a. As long as specimens like T. rigens<br />
a<strong>re</strong> excluded from collections identified as T. inclinata,<br />
that latter species is <strong>re</strong>adily identifiable, and so it is in<br />
North American populations that half <strong>of</strong> the specimens<br />
<strong>of</strong> T. rigens we<strong>re</strong> found among herbarium collections <strong>of</strong><br />
T. inclinata.<br />
Neither Albertson (1946) nor Crundwell and<br />
Nyholm (1962) stated that populations with morphology<br />
intermediate between any <strong>of</strong> the Tortella species in<br />
Sweden occur in southern Scandinavia, although "in the<br />
alvar vegetation <strong>of</strong> Öland and Gotland, whe<strong>re</strong> the<br />
underlying limestone is cove<strong>re</strong>d by only a very thin<br />
layer <strong>of</strong> soil, they [T. inclinata and T. densa] do <strong>of</strong>ten<br />
occur together, associated with T. tortuosa, T. fragilis,<br />
and T. rigens. These five species f<strong>re</strong>quently grow in<br />
mixed tufts, without intermediates" (Crundwell &<br />
Nyholm 1962). Whether intermediate plants will be<br />
found in North America <strong>re</strong>qui<strong>re</strong>s additional field work.<br />
After examining numerous Scandinavian<br />
specimens from S, several identified by either<br />
Crundwell or Nyholm or both, the following may be<br />
said:<br />
1. The statu<strong>re</strong> <strong>of</strong> Swedish plants is variable,<br />
from short to rather long. When the stems (so far only<br />
seen in Europe) a<strong>re</strong> as long as those <strong>of</strong> Tortella fragilis,<br />
that is usually what the plant is. Characteristic <strong>of</strong> T.<br />
rigens populations is intergradation between forms short<br />
enough to pass as T. inclinata to material that may pass<br />
as T. fragilis or T. tortuosa. Neither T. inclinata, T.<br />
fragilis, or T. tortuosa populations show this<br />
intergradation <strong>of</strong> statu<strong>re</strong>.<br />
2. The leaf variation in herbarium specimens<br />
ranges from short incurving to cucullate leaves to longer<br />
leaves that begin to show a diffe<strong>re</strong>ntiation in the distal<br />
<strong>re</strong>gion into a not very well-developed deciduous<br />
propagulum, usually one or two leaves <strong>of</strong> which a<strong>re</strong><br />
marginally borde<strong>re</strong>d by thick-walled, smooth, elongate<br />
cells, similar to that <strong>of</strong> Tortella fragilis.<br />
3. The leaf cross-section is intermediate<br />
between Tortella fragilis, with its bistratose distal leaf<br />
section in the <strong>re</strong>gion whe<strong>re</strong> the propagulum is forming,<br />
and T. inclinata, with a <strong>re</strong>latively broad a<strong>re</strong>a (to two<br />
ste<strong>re</strong>id cells wide) on the adaxial surface <strong>of</strong> the costa<br />
that has no quadrate papillose cells. This is not as broad<br />
as the exposed a<strong>re</strong>a <strong>of</strong> T. inclinata, which <strong>of</strong>ten th<strong>re</strong>e<br />
ste<strong>re</strong>id cells wide.<br />
43<br />
4. Neither Tortella fragilis nor T. inclinata<br />
has a stem central strand: no such featu<strong>re</strong> has been<br />
found in specimens <strong>of</strong> Tortella rigens either.<br />
5. Leaf cell sizes a<strong>re</strong> consistently 14 µm or<br />
larger. Those <strong>of</strong> Tortella inclinata a<strong>re</strong> rather large (to 12<br />
µm) and those <strong>of</strong> T. fragilis occasionally can attain that<br />
dimension.<br />
The specimens on which Weber (1973) based<br />
his description and discussion <strong>of</strong> Tortella rigens from<br />
the American West (Colorado) we<strong>re</strong> <strong>re</strong>determined to be<br />
T. alpicola—a species with leaf cell sizes identical to<br />
those described for the former species, and which also<br />
have deciduous leaf apices. The structu<strong>re</strong> <strong>of</strong> Tortella<br />
alpicola is quite diffe<strong>re</strong>nt from T. rigens (see discussion<br />
above).<br />
Depauperate plants <strong>of</strong> Tortella fragilis account<br />
for the other specimens and <strong>re</strong>ports <strong>of</strong> T. rigens, hence<br />
the p<strong>re</strong>sent study p<strong>re</strong>sents the first genuine <strong>re</strong>ports for<br />
North America. A specimen from Larimer County,<br />
Colorado (Hermann 27641, MICH, NY) from the<br />
Rocky Mountain National Park in moist tundra at<br />
11,600 feet had plants <strong>of</strong> a vivid g<strong>re</strong>en. It <strong>re</strong>sembled<br />
Tortella rigens superficially in the small plants, in the<br />
foliose habit with less stiff leaves and larger leaf cells<br />
(from 11 to 14 µm). However, none <strong>of</strong> the leaves we<strong>re</strong><br />
tubulose or subcucullate, all had quadrate, papillose<br />
cells on the adaxial costa surface in the median leaf<strong>re</strong>gion.<br />
As the collector himself noted, the apex was<br />
fully bistratose and lanceolate-subulate leaves with<br />
complete propaguloid modifications together with the<br />
border <strong>of</strong> elongate, thicker walled, smooth cells typical<br />
<strong>of</strong> T. fragilis we<strong>re</strong> found in at least some leaves. This<br />
latter characteristic p<strong>re</strong>cluded the specimen being<br />
identified as T. rigens, although the plant was striking<br />
for the unusually few leaves with such modifications<br />
and the <strong>re</strong>latively short subulae, when they did occur.<br />
Habitat diffe<strong>re</strong>nces may also be brought to bear:<br />
Tortella rigens occurs on flat calca<strong>re</strong>ous alvar<br />
pavements near sea level.<br />
Hermann 27264 (DUKE, MICH) from<br />
Gunison County, Colorado at 12,162 ft. (3685 m), in<br />
"wet, peaty vertical bank <strong>of</strong> pond on tundra" was also<br />
similarly modified Tortella fragilis with the same<br />
characters as noted above.<br />
All specimens <strong>of</strong> Tortella fragilis in North<br />
America and identified as T. rigens always had long- to<br />
linear-lanceolate leaves (typical <strong>of</strong> T. fragilis) and<br />
always had a fully completely developed apical<br />
propagulum in at least a few leaves and quadrate,<br />
papillose cells across the adaxial surface <strong>of</strong> the costa.<br />
Even minute specimens <strong>of</strong> this species from Quebec<br />
showed the typical cylindrical apical propagula at the<br />
tips <strong>of</strong> the youngest leaves emerging from the stem<br />
apex.<br />
The cells sizes a<strong>re</strong> undoubtedly large in<br />
Tortella rigens (14 and even to 17 µm), but such cells<br />
sizes (to 14 µm) cor<strong>re</strong>lated with <strong>re</strong>duced apical<br />
propagula can be demonstrated in the two American<br />
specimens <strong>of</strong> T. fragilis collected by F. Hermann. Large<br />
cell sizes can be demonstrated in some northern
collections <strong>of</strong> T. tortuosa as well and, as noted by<br />
Crundwell and Nyholm (1962) above, <strong>re</strong>garding T.<br />
flavovi<strong>re</strong>ns var. glariecola, large cell size may be a<br />
northern condition <strong>of</strong> species with otherwise smaller<br />
cell sizes. Depauperate specimens <strong>of</strong> Tortella fragilis<br />
with large leaf cell sizes may be demonstrated in the<br />
Southern Hemisphe<strong>re</strong> as well, such as in specimens<br />
from Campbell Island (Eckel 1997). These specimens<br />
have quadrate, papillose cells covering the adaxial<br />
surface <strong>of</strong> the costa.<br />
Specimens examined:<br />
N.Y.: Jefferson Co., limestone pavement, east <strong>of</strong><br />
Rosie<strong>re</strong>, ca. 340 ft. (110 m), July 9, 1968, S. J.<br />
Smith & W. V. Glider 42789 (MICH).<br />
This specimen is intriguing in that it is a mixtu<strong>re</strong> <strong>of</strong><br />
Tortella rigens and a perichaetiate plant that at first<br />
appea<strong>re</strong>d to be an ar<strong>re</strong>sted form <strong>of</strong> T. fragilis: the latter<br />
plant had everything but the propaguloid leaf apices and<br />
the completely bi-multi-stratose distal leaf cross section<br />
<strong>of</strong> that species. The plant with stiff leaves, deciduous<br />
apices, the marginal elongate, non-papillose cells was<br />
identified as T. tortuosa var. fragilifolia, complete with<br />
bistratose cells juxtacostally and leaf laminal cells<br />
gradually smaller toward the margins. The var.<br />
fragilifolia is rigid, lacks leaf apices on most matu<strong>re</strong><br />
leaves and is a bleached yellow-brown with small cells<br />
and quadrate papillose cells on the adaxial surface <strong>of</strong> the<br />
costa; the T. rigens is broadly lanceolate and a dull<br />
g<strong>re</strong>enish black with all its apices intact and with large<br />
leaf cells and quadrate, papillose cells absent in a<br />
narrow groove on the adaxial surface <strong>of</strong> the costa<br />
throughout the leaf.<br />
Additional specimens examined:<br />
Ont.: Renf<strong>re</strong>w Co.: Eganville, Grattan Township,<br />
45°31'N, 77°00'W, limestone bluffs along river<br />
and adjacent conifer-mixed wood habitat,<br />
limestone pavement in clearing beside river, R.<br />
R. I<strong>re</strong>land 22735, July 20, 1987 (NY) (also<br />
22737 UBC, same a<strong>re</strong>a and time: dark g<strong>re</strong>enblack).<br />
Ont.: Cochrane District, along Stone Rapids, Scovil Tp.,<br />
600 ft. (180 m), growing along rocky sho<strong>re</strong>,<br />
Aug. 1976, Garry A. Shea (CANM).<br />
Ohio, Ottawa Co. Marblehead quarry, limestone rock,<br />
Opuntia bar<strong>re</strong>n, C. M. Boardman, Aug. 7,<br />
1953, C. M. Boardman, Aug. 8, 1955 (DUKE)<br />
(plants perichaetiate).<br />
Mich.: Chippewa Co., on box limestone a<strong>re</strong>a, very<br />
abundant, just N <strong>of</strong> Fork Kampe Y in road,<br />
Sec. 34 T43N R6E, Drummond Island, June<br />
28/9, 1948, L. F. Koch 2630 (CANM, very<br />
robust specimen).<br />
N.Y.: Jefferson Co., limestone pavement, east <strong>of</strong><br />
Rosie<strong>re</strong>, ca. 340 ft. (130 m), July 9, 1968, S. J.<br />
Smith & W. V. Glider 42789 (MICH) (plants<br />
perichaetiate).<br />
44<br />
A protonematous specimen from Michigan<br />
(Emmet Co. "on quartz pebbles on sandy beach" I<strong>re</strong>land<br />
4362a (CANM), identified as T. inclinata is clearly<br />
anomalous: it has very large leaf-cells, to 14 µm and<br />
larger, has undulate leaves and acute to acuminate<br />
apices. It is unlikely to be T. inclinata and might be<br />
<strong>re</strong>ferable to T. rigens, but the specimen is too<br />
depauperate and too peculiar to assess with confidence.<br />
8. TORTELLA NITIDA Plate 9<br />
Tortella nitida (Lindb.) Broth., Nat. Pfl. 1(3): 397.<br />
1902.<br />
Tortula nitida Lindb., Öfv. K. Vet. Ak. Ferh.<br />
21: 252. 1864. Type: Gibraltar, A. F.<br />
Regnell. 1839 (S—isotype).<br />
Barbula alexandrina Lor., Abh. Ak. Wiss.<br />
Berlin 1867: 31. 6, 7. 1868. [The date<br />
<strong>of</strong> publication <strong>of</strong> this species was<br />
1867, fide Stafleu & Cowan 1981:<br />
159.]<br />
Trichostomum diffractum Mitt., J. Bot. 6: 98.<br />
77 f. 5, 6. 1868.<br />
Trichostomum nitidum (Lindb.) Schimp., Syn.<br />
ed. 2: 179. 1876.<br />
Mollia nitida (Lindb.) Lindb. in Braithw., Brit.<br />
Moss Fl. 1: 250. 37 A. 1887.<br />
Plants in dull olive-g<strong>re</strong>en to yellowish-g<strong>re</strong>en, dense,<br />
rounded cushions, compact, the habit elongate, not<br />
rosulate. Stems 0.5–2 cm high, forked, densely foliose,<br />
leaf bases hidden, tomentum confined to the base <strong>of</strong> the<br />
stem, hyalodermis well developed, central strand strong,<br />
in older stems <strong>of</strong>ten pigmented around a central apertu<strong>re</strong><br />
lacking tissue. Stem leaves once-circinately incurved<br />
when dry, e<strong>re</strong>ct to e<strong>re</strong>ct-sp<strong>re</strong>ading when moist, typically<br />
very fragile to moderately so, distal part <strong>of</strong> leaf usually<br />
missing, to 4 mm long, ligulate, oblong, oblongspathulate<br />
to broadly lanceolate, appearing mo<strong>re</strong><br />
narrowly lanceolate in strongly tubulose leaves, mostly<br />
broadly acute to acute, broadly channeled, nearly flat to<br />
somewhat to strongly tubulose in the distal portion <strong>of</strong><br />
the leaf, leaves f<strong>re</strong>quently naviculate; base ovate,<br />
somewhat broader than above, <strong>of</strong>ten diffe<strong>re</strong>ntiated from<br />
the distal part <strong>of</strong> the leaf by a constriction (wasp-waist)<br />
or, if the distal lamina is strongly incurved, appearing<br />
with shoulders, if proximal cells a<strong>re</strong> particularly lax,<br />
appearing narrower than the distal portion <strong>of</strong> the leaf<br />
from the sides <strong>of</strong> the leaf folded inwards at the base;<br />
margins broadly to strongly incurved-involute, then<br />
e<strong>re</strong>ct just befo<strong>re</strong> the apex, <strong>of</strong>ten appearing cucullate at<br />
least in some leaves; apex obtuse to broadly to narrowly<br />
acute, sometimes appearing emarginate due to the<br />
erosion <strong>of</strong> the mucro, the mucro <strong>of</strong>ten p<strong>re</strong>ceded by brief<br />
channel or excavation on the adaxial surface <strong>of</strong> the<br />
costa, this condition contributing to the tip <strong>of</strong> the apex<br />
<strong>of</strong>ten bent backwards, occasionally the distal third<br />
<strong>re</strong>gion <strong>of</strong> the leaf becoming long-acuminate and narrow<br />
above a broader proximal two-thirds, the costa excur<strong>re</strong>nt<br />
into a longer, mo<strong>re</strong> sharply tipped mucro; costa thick,
elatively broad, a brown, rather than stramineous color,<br />
short-excur<strong>re</strong>nt into a broad, bluntly conic mucro <strong>of</strong> 3–5<br />
cells, in leaves <strong>of</strong> young plants the mucro may be<br />
extended into a sharp, denticulate subhyaline point, or in<br />
specimens from <strong>re</strong>gions at higher elevations, the mucro<br />
may be longe and composed <strong>of</strong> many cells; adaxial<br />
surface <strong>of</strong> the costa cove<strong>re</strong>d throughout by quadrate<br />
papillose cells, absent in a narrow groove at the ext<strong>re</strong>me<br />
leaf apex; in section prominently rounded due to well<br />
developed abaxial and adaxial ste<strong>re</strong>id layer and a<br />
distinctive and well-developed adaxial epidermis<br />
forming a palisade <strong>of</strong> <strong>of</strong>ten vertically elongated, narrow,<br />
thin-walled papillose cells throughout the leaf, the<br />
junctu<strong>re</strong> <strong>of</strong> lamina and costa occasionally marked by<br />
incomplete double layers <strong>of</strong> either laminal, guide or<br />
adaxial epidermal cells, in cross section lunate and flat<br />
to convex adaxially, in the proximal median <strong>re</strong>gion<br />
occasionally with a partially bistratose adaxial<br />
epidermis, guide cells in a partially double row, nearly<br />
always with at least one extra guide cell abaxial or<br />
adaxial to the guide cell layer, i.e. in a bistratose guide<br />
cell pair; proximal laminal cells smooth, mostly thickwalled<br />
except for the proximal leaf margin, gradually<br />
diffe<strong>re</strong>ntiated in size and cell-wall thickness across the<br />
proximal portion, elongate, 6:1, somewhat inflated,<br />
hyaline-yellowish, rather firm-walled at the insertion,<br />
appearing borde<strong>re</strong>d at the base by a marginal band <strong>of</strong><br />
thinner-walled, firm to lax elongate cells, <strong>of</strong>ten to 7<br />
cells wide, <strong>re</strong>duced to one cell wide distally and<br />
continuing a short distance up the margins, or the<br />
margin not diffe<strong>re</strong>ntiated except for a proximal marginal<br />
border <strong>of</strong> somewhat mo<strong>re</strong> delicate and <strong>re</strong>latively<br />
elongate cells, distal laminal cells 7–10 µm wide,<br />
unistratose, marginal cells undiffe<strong>re</strong>ntiated, evenly<br />
papillose-c<strong>re</strong>nulate, some leaves variously undulate.<br />
Asexual <strong>re</strong>production by a fragile lamina. Sexual<br />
condition dioicous. Perigonia not seen. Perichaetia<br />
terminal, leaves little diffe<strong>re</strong>ntiated from cauline leaves,<br />
lamina <strong>of</strong> the inner perichaetial leaves somewhat<br />
narrowed apically, the mucro mo<strong>re</strong> pronounced. Seta<br />
dark orange below, becoming paler above, 1.7–1.8 cm<br />
long. Capsule 3–3.5 mm long, operculum 1–1.2 mm,<br />
conic, appearing mo<strong>re</strong> subulate when immatu<strong>re</strong>;<br />
peristome teeth elongate, ca. 0.5 mm, e<strong>re</strong>ct to omewhat<br />
inclined, orange-<strong>re</strong>d (same color as the capsule),<br />
densely spiculose. Calyptra: not seen. Spo<strong>re</strong>s light<br />
brown, nearly smooth or distinctly papillose, 9–11 µm.<br />
Herbaria examined: BUF, CANM, MT, NY,<br />
NYS, S.<br />
Smith (1978) cited the substrate (in Britain)<br />
and the species distribution as: "On basic rocks and<br />
walls in W. and SW Britain, W I<strong>re</strong>land and Jersey. C.<br />
Europe, S.W. Asia, N. Africa, N. America." It "is the<br />
most common Tortella species <strong>of</strong> the Macaronesian<br />
Islands (May 1986), whe<strong>re</strong> it occurs on lava cliffs, on<br />
sloping rocks, f<strong>re</strong>quently on "calca<strong>re</strong>ous walls" in towns<br />
(see May 1986 for details). Limpricht (1890) <strong>re</strong>ported it<br />
as a species <strong>of</strong> the Mediterranean <strong>re</strong>gion as did<br />
Braunmiller et al. (1971) "with outliers in the warmest<br />
45<br />
<strong>re</strong>gions <strong>of</strong> central Europe...," although these authors<br />
did not discuss or map its distribution the<strong>re</strong>.<br />
In Britain, "Recognisable by the leaves tightly<br />
incurved when dry, the neat, rounded tufts and the<br />
fragile leaves. Has been confused with Tortella<br />
flavovi<strong>re</strong>ns but differs in habit, habitat and in the<br />
transition from proximal hyaline to chlorophyllose cells<br />
being not very abrupt" (Smith 1978). One might expect<br />
T. nitida to be found in our southern states, associated<br />
with and in the range <strong>of</strong> T. flavovi<strong>re</strong>ns as it is in the<br />
warmer parts <strong>of</strong> G<strong>re</strong>ater Britain, but to date only North<br />
Temperate stations have been <strong>re</strong>ported for North<br />
America, while the p<strong>re</strong>sent study excludes it enti<strong>re</strong>ly.<br />
Braithwaite (Brit. Moss Fl. 1: 250. 37 A. 1887)<br />
appears to have been the first to include in his<br />
synonymy <strong>of</strong> Tortella nitida: "Trichostomum barbula<br />
(non Schwaeg.) Lange, in Bot. Tids. ii, 235 (1868)."<br />
Podpera (1954) also cited the same publication in his<br />
synonymy <strong>of</strong> Tortella nitida. The Index Muscorum<br />
citation (Van der Wijk et al. 1958–69) is:<br />
"Trichostomum barbula Lang., Bot. Tidskr. 2: 235.<br />
1868 hom. illeg. = Tortella nitida (Lindb.) Broth. fid.<br />
Grout, Moss Fl. N. Am. 1: 169. 1938." Lange's<br />
publication is a checklist <strong>of</strong> the mosses <strong>of</strong> Tuscany<br />
"Toscanske Mosser, et bryologisk Bidrag" on pages<br />
226–254 and on page 235 is a simple statement that<br />
Trichostomum barbula Schwaegr. occurs in Tuscany. It<br />
is not clear how authors have p<strong>re</strong>sumed Lange to have<br />
been proposing a nomenclatural change on this page<br />
having to do with Tortella nitida, a name published only<br />
a few years earlier. The<strong>re</strong> seems to be no <strong>re</strong>ason to<br />
assume that Trichostomum barbula Schwaegr. as used<br />
by Lange was not meant to <strong>re</strong>p<strong>re</strong>sent Timmiella<br />
barbuloides (Brid.) Mönk., a species that also occurs in<br />
Italy.<br />
Tortella nitida and Timmiella barbuloides do<br />
<strong>re</strong>semble one another. May (1986) for Macaronesia,<br />
warned that "if one finds "Tortella nitida with<br />
sporophytes in abundance, one should check for<br />
Timmiella barbuloides, which looks similar in habit, but<br />
is easily <strong>re</strong>cognised...by the bistratose, mamillose<br />
lamina <strong>of</strong> the leaf." Timmiella barbuloides also has a<br />
serrate leaf apex.<br />
The delimitation <strong>of</strong> Tortella nitida in Europe<br />
has been problematical for nearly a century. No<br />
extensive systematic study <strong>of</strong> Tortella species in Europe<br />
was undertaken in this study, hence no attempt was<br />
made to understand or conclusively <strong>re</strong>solve the<br />
somewhat uncertain status <strong>of</strong> this species. It was<br />
decided that a description based on the type specimen<br />
and one fruiting specimen that <strong>re</strong>sembled the type in all<br />
<strong>of</strong> its characteristics was adequate as a basis for<br />
discussion, and the least potentially misleading,<br />
especially as the descriptive tradition in both the New<br />
and Old World literatu<strong>re</strong> is inadequate and contradictory<br />
in various deg<strong>re</strong>es. Other material from Europe was also<br />
examined.<br />
Limpricht (1890) suggested that "the<br />
<strong>re</strong>semblance <strong>of</strong> the habit [<strong>of</strong> Tortella nitida] to Tortella<br />
inclinata etc. was the <strong>re</strong>ason that one could long not
ag<strong>re</strong>e about this species." He put T. nitida in the genus<br />
Trichostomum in the basis <strong>of</strong> the p<strong>re</strong>sence <strong>of</strong> a stem<br />
central strand.<br />
The type specimen <strong>of</strong> Tortella nitida strongly<br />
<strong>re</strong>sembles the autoicous Tortella humilis except for the<br />
massive costa, in section with two well-developed<br />
ste<strong>re</strong>id bands. It is perhaps because <strong>of</strong> this that<br />
Limpricht (1890) wonde<strong>re</strong>d whether T. nitida might<br />
possess axillary male buds. Tortella nitida differs from<br />
T. humilis immediately by its long stem and elongate<br />
habit, rather than the typically much shorter stem and<br />
rosulate habit <strong>of</strong> T. humilis. The cross section <strong>of</strong> T.<br />
humilis in the middle <strong>of</strong> the leaf is adaxially flat.<br />
Although the type <strong>of</strong> T. nitida has leaves that appear<br />
adaxially flat, most specimens a<strong>re</strong> mo<strong>re</strong> tubulose, with<br />
margins e<strong>re</strong>ct and broadly incurved. Although both<br />
species have gradually intergrading proximal cells,<br />
those <strong>of</strong> T. nitida a<strong>re</strong> mo<strong>re</strong> strongly intergrading: the<br />
marginal cells in the proximal a<strong>re</strong>a a<strong>re</strong> mo<strong>re</strong><br />
conspicuously set <strong>of</strong>f as a border <strong>of</strong> lax-walled,<br />
elongate, hyaline epapillose cells, in some specimens so<br />
<strong>re</strong>duced as to cast doubt that the specimen is a Tortella<br />
at all. Tortella nitida ra<strong>re</strong>ly fruits and has short, e<strong>re</strong>ct<br />
peristome teeth, whe<strong>re</strong>as T. humilis, at least in North<br />
America, is ra<strong>re</strong>ly found without fruit, and its peristome<br />
teeth a<strong>re</strong> long and in one or two spirals.<br />
Tortella nitida has a distinctive growth-form:<br />
in hemispherical cushions, rather like some Grimmia<br />
species, and is f<strong>re</strong>quently <strong>re</strong>p<strong>re</strong>sented in herbarium<br />
specimens as fan-shaped slices from the original polster.<br />
None <strong>of</strong> the species <strong>of</strong> Tortella that occur in North<br />
America assume this shape except T. inclinata var.<br />
densa.<br />
Tortella nitida has f<strong>re</strong>quently been described as<br />
having a "white" or "pale" costa. Its costa seems,<br />
however, to be in color no diffe<strong>re</strong>nt than others in the<br />
genus, except that the costa itself is mo<strong>re</strong> prominent<br />
than in other species, especially when the laminae a<strong>re</strong><br />
folded together when dry and the whole clump <strong>of</strong> leaves<br />
p<strong>re</strong>sent their broad backs to view. This whiteness or<br />
paleness appa<strong>re</strong>ntly is in <strong>re</strong>fe<strong>re</strong>nce to the "gloss" due to<br />
the smoothness <strong>of</strong> the costal abaxial surface. The costae<br />
<strong>of</strong> all species in the genus a<strong>re</strong> yellow or yellow-brown<br />
to orange.<br />
The leaf cross section in highly colo<strong>re</strong>d<br />
specimens <strong>of</strong> Tortella nitida shows a palisade <strong>of</strong><br />
quadrate papillose cells on the adaxial surface <strong>of</strong> the<br />
costa forming a g<strong>re</strong>en layer over the orange costa,<br />
confluent with the g<strong>re</strong>en color <strong>of</strong> both laminae. The 1-3<br />
bistratose pairs <strong>of</strong> guide cells, or incompletely bistratose<br />
guide cell layer, is characteristic <strong>of</strong> Pseudosymblepharis<br />
and some species <strong>of</strong> Trichostomum (Zander 1993).<br />
Specimens from Europe show Tortella nitida<br />
to give little indication <strong>of</strong> its placement in Tortella<br />
except for a narrow border <strong>of</strong> about two to several cells<br />
width <strong>of</strong> elongate, thin-walled, smooth hyaline cells,<br />
otherwise the proximal cells a<strong>re</strong> all thick-walled,<br />
colo<strong>re</strong>d and gradually become diffe<strong>re</strong>ntiated from the<br />
distal laminal cells. Sometimes the hyaline border is<br />
46<br />
wider and distinct, <strong>re</strong>sembling that <strong>of</strong> Plerurochaete<br />
squarrosa (Brid.) Lindb.<br />
The fragility <strong>of</strong> the leaf <strong>of</strong> Tortella nitida <strong>of</strong>ten<br />
exp<strong>re</strong>sses itself in moderately scalloped or lobed<br />
margins, with indentations at points <strong>of</strong> laminal fragility.<br />
The leaves fragment in <strong>re</strong>ctangular units and along the<br />
length <strong>of</strong> the costa such that in many older leaves the<br />
stem is invested with naked costae divested <strong>of</strong> the<br />
laminae.<br />
None <strong>of</strong> the common ovate-lanceolate-leaved<br />
Trichostomum species have fragile leaves.<br />
Trichostomum tenuirost<strong>re</strong>, in North Temperate stations,<br />
may have fragile, tatte<strong>re</strong>d generally long-linear leaves<br />
with a sprawling, loosely tufted habit, occurring with or<br />
without a stem central strand. Tortella alpicola is<br />
similarly fragile and is separated by its diminutive size,<br />
large leaf cells and propagulum at the leaf tip. It is this<br />
fragility that helps to distinguish ambiguous specimens<br />
<strong>of</strong> Tortella nitida from Trichostomum brachydontium or<br />
Tr. crispulum, since some specimens <strong>of</strong> the latter<br />
species may show a tendency toward mo<strong>re</strong> delicate cells<br />
on the margins <strong>of</strong> an otherwise intergrading proximal<br />
cell <strong>re</strong>gion.<br />
Although most <strong>re</strong>gional floras do not mention<br />
it, neither Trichostomum crispulum nor Tr.<br />
brachydontium a<strong>re</strong> tomentose except at the base, and in<br />
this characteristic Tortella nitida is similar.<br />
William Mitten's isotype (NY) <strong>of</strong><br />
Trichostomum diffractum Mitt., now included in the<br />
synonymy <strong>of</strong> Tortella nitida, was also examined and,<br />
although <strong>re</strong>p<strong>re</strong>senting rather smaller plants with<br />
narrower leaves, perhaps characteristic <strong>of</strong> immaturity, it<br />
matches Lindberg's type. Other collections made by<br />
Mitten in Britain also closely <strong>re</strong>semble the Lindberg<br />
type.<br />
The description and illustration <strong>of</strong> fruiting<br />
material he<strong>re</strong> is taken from a single specimen:<br />
Dalmatian plants collected by Jul. Baumgartner 16/III<br />
1904 (S). Clearly the description and illustration <strong>of</strong> the<br />
peristome <strong>of</strong> this specimen in the p<strong>re</strong>sent manuscript<br />
does not match what is described by the following<br />
sources: "peristome teeth short, rather imperfect, very<br />
slightly oblique" (Dixon 1924); "peristome short, <strong>of</strong><br />
rather imperfect, very slightly oblique, yellowish,<br />
papillose teeth" (Haring 1938); "Teeth <strong>of</strong> the peristome<br />
very short and ir<strong>re</strong>gular, truncate, yellow, papillose"<br />
(Braithwaite 1887). Mönkemeyer (1927) also indicated<br />
that the peristome <strong>of</strong> Tortella nitida was rudimentary.<br />
Limpricht (1890), in addition, <strong>re</strong>ported that the cells <strong>of</strong><br />
the operculum we<strong>re</strong> straight, the peristome was<br />
rudimentary, yellow-<strong>re</strong>d and smooth, although Philibert<br />
described the teeth as papillose, the basal tube scarcely<br />
or not at all exserted, the teeth linear, scarcely<br />
developed, the longest to 0.07 mm. He appears to have<br />
seen a fruiting specimen, although the species<br />
appa<strong>re</strong>ntly did not fruit in Germany, Austria or<br />
Switzerland.<br />
The peristome teeth in Braithwaite's illustration<br />
(1887: pl. 37 and <strong>re</strong>produced by Haring in Grout 1938:<br />
169, pl. 81) a<strong>re</strong> very short with <strong>re</strong>spect to the capsule
length, not at all like the illustration provided for the<br />
p<strong>re</strong>sent paper, drawn from a collection that displays all<br />
the gametophyte characteristics <strong>of</strong> the type <strong>of</strong> Tortella<br />
nitida. The Dalmatian peristome in the p<strong>re</strong>sent paper's<br />
illustration is no mo<strong>re</strong> rudimentary than that <strong>of</strong> T.<br />
flavovi<strong>re</strong>ns, which is never described as rudimentary; it<br />
is about half the length <strong>of</strong> that <strong>of</strong> T. tortuosa or T.<br />
humilis. It may be that the peristome <strong>of</strong> T. nitida is<br />
variable or that past authors have misidentified the<br />
specimens they described—mo<strong>re</strong> study is warranted.<br />
As stated above in the discussions under<br />
Tortella alpicola and T. tortuosa var. fragilifolia, North<br />
American material seen labeled as T. nitida proved to be<br />
T. alpicola, T. fragilis, T. tortuosa, Trichostomum<br />
tenuirost<strong>re</strong> and Tortella tortuosa var. fragilifolia.<br />
Some note must be made <strong>of</strong> a particular kind <strong>of</strong><br />
variation in Tortella nitida in Europe as it may or may<br />
not contribute information <strong>of</strong> <strong>re</strong>levance to patterns <strong>of</strong><br />
variation in T. tortuosa and T. inclinata in North<br />
America. Although the problem could not be add<strong>re</strong>ssed<br />
in the p<strong>re</strong>sent study and so concluded to satisfaction,<br />
the<strong>re</strong> is variation in T. nitida that seems to parallel that<br />
<strong>of</strong> T. tortuosa var. fragilifolia and T. rigens, the latter<br />
possibly a hybrid <strong>of</strong> T. inclinata with T. fragilis.<br />
Tortella tortuosa var. fragilifolia and T. rigens,<br />
primarily in Europe, a<strong>re</strong> characterized by having<br />
deciduous modifications in the leaf tip. My own<br />
experience with this variation is that the leaf apices<br />
become mo<strong>re</strong> rigid, elongate (leaf apices becoming<br />
acuminate and the leaf appearing mo<strong>re</strong> linear-lanceolate<br />
than typical), parallel-sided and fragile. Also they may<br />
exhibit a single-laye<strong>re</strong>d border <strong>of</strong> elongate, smooth to<br />
smoother cells, a section showing bistratose juxtacostal<br />
cells, and the leaf tip may tend to become cylindrical,<br />
hence the back <strong>of</strong> the costa may exhibit quadrate<br />
papillose cells, all <strong>of</strong> these characteristics most<br />
strikingly displayed in Tortella fragilis. May (1986) in<br />
his discussion <strong>of</strong> T. nitida in Macaronesia described the<br />
var. irrigata as differing in having a mo<strong>re</strong> acuminate<br />
non-cucullate leaf than the typical variety and that at the<br />
apex "on the dorsal side in the upper part cove<strong>re</strong>d with<br />
quadrate, papillose lamina cells," and which is<br />
otherwise as in the typical variety. May also showed<br />
with excellent illustrations the characters <strong>of</strong> T. nitida.<br />
Another variety, T. nitida var. subtortuosa<br />
(Boul.) Jelenc, may indicate a similar variation, but<br />
further study is <strong>re</strong>qui<strong>re</strong>d. Any special deciduous natu<strong>re</strong><br />
<strong>of</strong> the apices <strong>of</strong> either variety would be obscu<strong>re</strong>d by the<br />
tendency <strong>of</strong> the species in general toward fragility. Both<br />
varieties a<strong>re</strong> distinguished from Tortella tortuosa var.<br />
fragilifolia or T. rigens by the well-defined stem central<br />
strand.<br />
Both types <strong>of</strong> variation in Tortella nitida a<strong>re</strong><br />
indicated in a series <strong>of</strong> specimens examined in loans<br />
from NY and S and the kind <strong>of</strong> variation described by<br />
May above is evident in many <strong>of</strong> them: these have a<br />
longer (mo<strong>re</strong> multi-cellular), sharply pointed denticulate<br />
mucro, rather than the short, blunt, smooth, conical<br />
mucro <strong>of</strong> the typical plant and the two types examined,<br />
and the leaves have long-acuminate apical leaf-quarters<br />
47<br />
with approximately parallel sides. Again, it appears<br />
as though tendencies toward apical modifications that<br />
<strong>re</strong>semble those <strong>of</strong> Tortella fragilis a<strong>re</strong> p<strong>re</strong>sent in T.<br />
nitida.<br />
Boulay (1884: 445) was <strong>re</strong>ported by Limpricht<br />
(1890) to distinguish th<strong>re</strong>e varieties <strong>of</strong> what is now<br />
called Tortella nitida: Tortella nitida var. obtusa (Boul.)<br />
Jelenc; T. nitida var. media (Boul.) Corb.; and (T. nitida<br />
var. subtortuosa (Boul.) Jelenc. What Limpricht did not<br />
say was that Boulay described these varieties as part <strong>of</strong><br />
the variation <strong>of</strong> what is now conside<strong>re</strong>d to be Tortella<br />
flavovi<strong>re</strong>ns (i.e. Trichostomum flavovi<strong>re</strong>ns), not Tortella<br />
nitida. I doubt one should assume that these varieties<br />
actually <strong>re</strong>p<strong>re</strong>sent significant variation in the<br />
morphology <strong>of</strong> T. nitida. They we<strong>re</strong> originally intended<br />
to describe variation in the (now known to be) coastally<br />
<strong>re</strong>stricted T. flavovi<strong>re</strong>ns.<br />
Upon examination <strong>of</strong> a series <strong>of</strong> European<br />
specimens <strong>of</strong> Tortella nitida from NY and S, it is<br />
possible to speculate that this species may be sensitive<br />
to altitudinal variation, perhaps similar to the variation<br />
he<strong>re</strong> attributed to T. inclinata s.l. The further away from<br />
the Alps and the nea<strong>re</strong>r to sea level, especially in the<br />
peripheral part <strong>of</strong> the range, the mo<strong>re</strong> the species<br />
<strong>re</strong>sembles the types both <strong>of</strong> Lindberg and <strong>of</strong> Mitten with<br />
ligulate-lanceolate leaves with generally obtuse to<br />
broadly acute apices. The Lindberg type derived from<br />
the Gibraltar a<strong>re</strong>a and the Mitten type from England.<br />
With higher altitude the leaves undergo an elongation<br />
and elaboration <strong>of</strong> the leaf apex: the proximal <strong>re</strong>gion<br />
stays the same, but the distal third <strong>of</strong> the leaf becomes<br />
acuminate, with quadrate cells on the back <strong>of</strong> the costa,<br />
with a long denticulate mucro and so forth. The types<br />
thus may <strong>re</strong>p<strong>re</strong>sent only variation at low altitudes,<br />
including islands in the Atlantic and the Mediterranean,<br />
coastal plains and interior plains <strong>re</strong>gions rather than<br />
upland <strong>re</strong>gions on the continent <strong>of</strong> Europe. Not enough<br />
material has been examined he<strong>re</strong> to substantiate this.<br />
The smallest plants (in stem length) in<br />
specimens we<strong>re</strong> seen from British stations. They we<strong>re</strong><br />
hard to separate from Trichostomum, especially Tr.<br />
crispulum and Tr. brachydontium, but at least some<br />
leaves had a proximal margin <strong>of</strong> cells that we<strong>re</strong> longer<br />
and mo<strong>re</strong> lax than the inner proximal cells, and this<br />
margin extended above the proximal <strong>re</strong>gion. They had<br />
indented or scalloped laminal margins in the distal<br />
<strong>re</strong>gion <strong>of</strong> the leaf, indicating that the leaves we<strong>re</strong> fragile<br />
and not simply eroded. The excur<strong>re</strong>nt costa in these<br />
small forms is <strong>of</strong> a few cells and <strong>re</strong>sembles mo<strong>re</strong> <strong>of</strong> an<br />
apiculus than a mucro.<br />
Belgian specimens we<strong>re</strong> <strong>of</strong> typical and<br />
intermediate forms. In Switzerland, one sees plants with<br />
typical leaves (<strong>re</strong>sembling those <strong>of</strong> Tortella humilis in<br />
shape: ligulate-lanceolate or broadly lanceolate) in the<br />
lower part <strong>of</strong> the stem. However, in the distal part <strong>of</strong> the<br />
stem, the younger leaves start to become mo<strong>re</strong> abruptly<br />
acuminate from a broader proximal 2/3 <strong>re</strong>gion. The<br />
distal acumination is further characterized by g<strong>re</strong>ater<br />
modifications for fragility (marginal indentations). The<br />
costa on the abaxial side has chlorophyllose, quadrate,
papillose cells (the var. irrigata, according to May 1986)<br />
and a longer mucro. This type <strong>of</strong> apical <strong>re</strong>gion may<br />
detach as a chlorophyllose propagule.<br />
Occasional specimens have been confused with<br />
Weissia species, whose proximal cells can <strong>re</strong>semble<br />
those <strong>of</strong> Tortella nitida, as a vaguely defined extension<br />
<strong>of</strong> the proximal marginal cells a short way up the<br />
lamina. While T. nitida can have broadly incurved distal<br />
margins in part, and sometimes this seems strong in the<br />
ext<strong>re</strong>me apex which then appears cucullate, species <strong>of</strong><br />
Weissia will have tightly and narrowly inflexed margins<br />
throughout the enti<strong>re</strong> distal 3/4 <strong>of</strong> the leaf.<br />
Specimens <strong>of</strong> Trichostomum brachydontium<br />
from Europe a<strong>re</strong> <strong>of</strong>ten confused with Tortella nitida. In<br />
the latter species, however, the leaves a<strong>re</strong> generally<br />
tubulose and the apex <strong>of</strong> at least some leaves appears or<br />
is subcucullate. In the former species, the leaf is flat<br />
throughout or is bounded by <strong>re</strong>latively sharply or<br />
abruptly upturned margins. The costa <strong>of</strong> Tr.<br />
brachydontium is mo<strong>re</strong> excur<strong>re</strong>nt than that <strong>of</strong> Tortella<br />
nitida, although appearing thick as is typical in that<br />
species, and <strong>re</strong>gularly comes to a smooth sharp point<br />
like a hard spike. While examining specimens from S,<br />
the<strong>re</strong> was a plant (Italy, A. Bottini May 1882) with the<br />
herbarium name "Tortula nitida var. acuminata<br />
Renauld," which had leaves with narrow apices and<br />
robust excur<strong>re</strong>nt denticulate costae (see illustration), but<br />
whose other characteristics a<strong>re</strong> typical. Trichostomum<br />
brachydontium is not fragile, its laminal margins a<strong>re</strong><br />
straight without indentations or scalloping, and it is<br />
difficult to demonstrate any marginal border <strong>of</strong><br />
proximal cells in any leaf.<br />
In North America, doubt must be cast on the<br />
likelihood that Haring (1938) saw North American<br />
fruiting material or even that <strong>of</strong> Europe, and her<br />
descriptions <strong>of</strong> the peristome seem to derive from the<br />
literatu<strong>re</strong>, particularly <strong>of</strong> Braithwaite (1887). This<br />
conjectu<strong>re</strong> is supported by the rarity <strong>of</strong> fruiting material<br />
<strong>of</strong> the species in Europe at the time <strong>of</strong> her publication:<br />
"...The fruit has only been found at<br />
Angouleme, in France, by M. Philibert in 1867, for<br />
some <strong>of</strong> whose specimens I am indebted to the kindness<br />
<strong>of</strong> M. Husnot" (Braithwaite 1887: 250–251, pl. 37A).<br />
Dixon acknowledged he had a "slight acquaintance with<br />
the fruiting plant" to hinder his final judgment on the<br />
placement <strong>of</strong> Tortella nitida: "indeed, it is probable that<br />
it will <strong>re</strong>main mo<strong>re</strong> or less doubtful until an opportunity<br />
is afforded <strong>of</strong> studying the fruit in good condition and in<br />
g<strong>re</strong>ater quantity. Hitherto it has only been found in two<br />
localities, the two plants p<strong>re</strong>senting certain diffe<strong>re</strong>nces<br />
<strong>of</strong> some importance in the structu<strong>re</strong> <strong>of</strong> their fruit and<br />
peristome..." (Dixon 1924). Since Dixon indicated that<br />
the species is sterile in Britain, one must assume that the<br />
two localities he mentioned a<strong>re</strong> <strong>of</strong> the fruiting material,<br />
and perhaps they a<strong>re</strong> from the same locality as<br />
Braithwaite's, if not the same specimens sent by<br />
Philibert.<br />
One might wonder if Philibert's specimens<br />
we<strong>re</strong> in fact Trichostomum brachydontium Bruch., a<br />
species with a rudimentary peristome, but having no<br />
48<br />
fragility in the leaves, having lax, thin-walled<br />
proximal cells. It has a <strong>re</strong>latively abrupt transition<br />
between distal laminal cells and proximal cells,<br />
something Tortella nitida would not. Mitten (1868)<br />
indicated both Tortella flavovi<strong>re</strong>ns and T. nitida to<br />
closely <strong>re</strong>semble Trichostomum brachydontium. The<br />
most obvious diffe<strong>re</strong>ntiating character <strong>of</strong> Tr.<br />
brachydontium is the horizontal or weakly U-shaped<br />
line that defines the distal limit <strong>of</strong> the hyaline proximal<br />
cells.<br />
In this context it seems inte<strong>re</strong>sting that Mitten<br />
also noted Tortella flavovi<strong>re</strong>ns to be mo<strong>re</strong> close in<br />
<strong>re</strong>semblance to Tortella humilis "than any other moss."<br />
He did not indicate that Tortella nitida is also close.<br />
Mitten also indicated the close <strong>re</strong>semblance <strong>of</strong> Tortella<br />
nitida (= Trichostomum diffractum) with Trichostomum<br />
brachydontium. Also, the closeness <strong>of</strong> Tr.<br />
brachydontium with Tortella flavovi<strong>re</strong>ns indicates that<br />
the th<strong>re</strong>e form a natural kind <strong>of</strong> group: all th<strong>re</strong>e have<br />
stem central strands, all th<strong>re</strong>e have mo<strong>re</strong> or less vaguely<br />
diffe<strong>re</strong>ntiated proximal cells, all th<strong>re</strong>e have diffe<strong>re</strong>nt<br />
peristomes (shorter and e<strong>re</strong>ct to rudimentary) than<br />
typical in the genus Tortella, which has long, once to<br />
twice spiralled peristome teeth.<br />
The name Tortella nitida as used by American<br />
authors (Haring 1938; Flowers 1973; Crum & Anderson<br />
1981) <strong>re</strong>fe<strong>re</strong>d to North American plants all with<br />
abruptly diffe<strong>re</strong>ntiated proximal cells, and the<strong>re</strong>fo<strong>re</strong><br />
which belong to other species. Crum and Anderson<br />
(1981) discussed North American <strong>re</strong>ports <strong>of</strong> Tortella<br />
nitida, including those made by Haring in Grout's Moss<br />
Flora, as Tortella tortuosa var. nitida (Lindb.) Pilous.<br />
However, the structu<strong>re</strong> <strong>of</strong> the stem in cross section with<br />
its distinctive central strand, the bistratose pairs in the<br />
guide cell layer <strong>of</strong> the leaf section, the gradually<br />
diffe<strong>re</strong>ntiated proximal cells, not to mention the<br />
anomalous peristome is a good basis for separating true<br />
T. nitida from T. tortuosa. Tortella tortuosa never<br />
develops the ligulate-lanceolate leaf at least <strong>of</strong> the type<br />
specimen <strong>of</strong> T. nitida.<br />
A specimen from Alaska collected by Hermann<br />
(21727, NY) identified as Tortella nitida is<br />
Trichostomum tenuirost<strong>re</strong>. Most <strong>of</strong> this collector's other<br />
specimens <strong>of</strong> T. nitida from North America a<strong>re</strong> Tortella<br />
alpicola.<br />
The specimen <strong>of</strong> Tortella nitida from the<br />
Northwest Territories cited by Stee<strong>re</strong> and Scotter (1978)<br />
76–620a could not be located at NY whe<strong>re</strong> the specimen<br />
was said to be deposited (Stee<strong>re</strong> 76–620 is Lophozia<br />
badensis, W. Buck, in litt.). The authors acknowledge in<br />
their paper that, according to Crum et al. (1973) "some<br />
doubt is cast...on whether it is p<strong>re</strong>sent in North America<br />
at all." The species was excluded from the North<br />
American flora by Crum et al. (1973). Although Crum<br />
and Anderson later (1981) mention a specimen <strong>of</strong><br />
Tortella nitida from the Nahanni P<strong>re</strong>serve, they do not<br />
comment on it further, perhaps because the specimen<br />
was not available for verification at that time either. If<br />
that particular collection followed the concept <strong>of</strong> Haring
(1938) or Flowers (1973), it was most likely Tortella<br />
alpicola or T. tortuosa var. fragilifolia.<br />
A citation <strong>of</strong> Tortella nitida as a literatu<strong>re</strong><br />
<strong>re</strong>port by I<strong>re</strong>land et al. (1987) for the Northwest<br />
Territories is probably a <strong>re</strong>fe<strong>re</strong>nce to the Stee<strong>re</strong> and<br />
Scotter paper (1978). A specimen determined to be<br />
Tortella nitida from Saskatchewan (Willow Bunch,<br />
Armand Filion, 13 Aug. 1927 MT) is Tortula<br />
mucronifolia Schwaegr. One may with confidence<br />
exclude this species from the moss flora <strong>of</strong> Canada as<br />
well as the United States.<br />
EXCLUDED TAXA<br />
Tortella mollissima Broth. ex Bartr.<br />
The specimen, kindly loaned by P. L.<br />
Redfearn, (<strong>Missouri</strong>: Douglas Co., along G<strong>re</strong>asy C<strong>re</strong>ek,<br />
2.5 miles SE <strong>of</strong> Ann, P. Redfearn 21330 (SMS),<br />
<strong>re</strong>ported as Tortella mollissima Broth. ex Bartr. by<br />
Redfearn (1969) is Trichostomum tenuirost<strong>re</strong> (Hook. &<br />
Tayl.) Lindb. Zander (1994) has made Tortella<br />
mollissima (with a Mexican type) a synonym <strong>of</strong><br />
Pseudosymblepharis schimperiana (Par.) Crum, a<br />
species <strong>of</strong> Mexico, Central America and Venezuela.<br />
Tortella nitida—see discussion above.<br />
ACKNOWLEDGEMENTS<br />
This paper is <strong>re</strong>spectfully p<strong>re</strong>sented in honor <strong>of</strong><br />
George Forman Goodyear in tribute <strong>of</strong> a lifetime <strong>of</strong><br />
distinguished cultural service to the people <strong>of</strong> Buffalo,<br />
New York. Michael Smith, Di<strong>re</strong>ctor <strong>of</strong> the Buffalo<br />
Museum <strong>of</strong> Science, and Richard Zander, Curator <strong>of</strong> the<br />
Clinton Herbarium allowed me <strong>re</strong>search facilities<br />
throughout the course <strong>of</strong> this study.<br />
I am grateful to Richard H. Zander for critical<br />
assistance throughout the p<strong>re</strong>paration <strong>of</strong> this manuscript<br />
and for permitting access to an unpublished manuscript<br />
t<strong>re</strong>atment <strong>of</strong> the genus Tortella in Arctic North<br />
America, and for help in translations from the F<strong>re</strong>nch.<br />
Gert Steen Mogensen gave information useful in the<br />
<strong>evaluation</strong> <strong>of</strong> Tortella arctica, critical bibliographical<br />
assistance and help with translations from the Swedish.<br />
I also thank R. Zander for kindly sharing with me<br />
detailed information provided by Hannes Hertel <strong>of</strong> the<br />
Botanische Staatssammlung (M), Munich, for data<br />
critical to designating a lectotype and for the loan <strong>of</strong><br />
specimens. A. C. Crundwell is thanked for useful<br />
comments on various species in the genus.<br />
Loans made by the curators <strong>of</strong> herbaria at the<br />
University <strong>of</strong> Alaska, the New York <strong>Botanical</strong> <strong>Garden</strong><br />
(NY); the New York State Herbarium, Albany (NYS);<br />
the University <strong>of</strong> Michigan, Ann Arbor (MICH); the<br />
<strong>Missouri</strong> <strong>Botanical</strong> <strong>Garden</strong> (MO); Duke University<br />
(DUKE); the National Museums <strong>of</strong> Canada, Ottawa<br />
(CANM); the Herbier Marie-Victorin, Universit‚ de<br />
Montr‚al (MT); the Mus‚um National d'Histoi<strong>re</strong><br />
Natu<strong>re</strong>lle, Paris; herbarium <strong>of</strong> the University <strong>of</strong> Alberta<br />
at Edmonton (ALTA); that <strong>of</strong> the University <strong>of</strong><br />
Colorado (COLO), the National Science Museum,<br />
49<br />
Tokyo (TNS); the University <strong>of</strong> Florida, Gainesville<br />
(FLA); the Swedish Museum <strong>of</strong> Natural History,<br />
Stockholm (S); the Farlow Cryptogamic Herbarium<br />
(Harvard University), the herbarium <strong>of</strong> the University <strong>of</strong><br />
British Columbia (UBC), the Herbarium <strong>of</strong> the<br />
University <strong>of</strong> Alaska (ALA), and the <strong>Botanical</strong> Institute,<br />
Christchurch, New Zealand (CHR) a<strong>re</strong> gratefully<br />
acknowledged. Special acknowledgement is made <strong>of</strong> the<br />
outstanding service <strong>of</strong> the curators at NY, cryptogamic<br />
collections, in the loan <strong>of</strong> critical specimens.<br />
BIBLIOGRAPHY<br />
AND SELECTED REFERENCES<br />
Abramova, A. L., L. I. Savicz-Ljubitzkaia and Z. N.<br />
Smirnova. 1961. Manual <strong>of</strong> the Leafy Mosses<br />
<strong>of</strong> the Arctic U.S.S.R. V.L. Komarov <strong>Botanical</strong><br />
Institute, Acad. Sci. USSR, Moscow,<br />
Leningrad.<br />
Albertson, N. 1946. Österplana Hed ett Alvaromr†de p†<br />
Kinnekulle. Uppsala.<br />
Anderson, L. E., H. A. Crum & W. R. Buck. 1990. List<br />
<strong>of</strong> the mosses <strong>of</strong> North America north <strong>of</strong><br />
Mexico. Bryologist 93(4): 448–499.<br />
Barnes, C. R. 1897. Analytic Keys to the Genera and<br />
Species <strong>of</strong> North American Mosses., <strong>re</strong>vised by<br />
F. D. Heald, University <strong>of</strong> Wisconsin P<strong>re</strong>ss,<br />
Madison Wisconsin.<br />
Boulay, J. N., Abbe. (1884). Muscinees de la France.<br />
Paris 1884–1904. 2 parts: P<strong>re</strong>mie<strong>re</strong> partie:<br />
Mousses. Nat. Nov. Sep 1884.<br />
Braithwaite, R. 1887–1905. The British Moss Flora.<br />
London. 3 vols.<br />
Belland, R. J. & G. R. Brassard. 1981. New or<br />
additional moss <strong>re</strong>cords from Newfoundland<br />
VII. Bryologist 84: 560–563.<br />
Braunmiller, H., J. Poelt, W. Schultze-Motel. 1971. šber<br />
die verb<strong>re</strong>itung einiger arten der<br />
laubmoosgattung Tortella in Mitteleuropa.<br />
Arch. Naturschutz und Landschaftsforsch,<br />
11(3): 169–178.<br />
Brotherus, V. F. 1924–1925. Musci. In A. Engler & K.<br />
Prantl, Die nat rlichen Pflanzenfamilien, Ed.<br />
2. 10: 1–478; 11: 1–542. Leipzig.<br />
Catling, P. M. & V. R. Brownell. 1995. A <strong>re</strong>view <strong>of</strong> the<br />
alvars <strong>of</strong> the G<strong>re</strong>at Lakes <strong>re</strong>gion: distribution,<br />
floristic composition, biogeography and<br />
protection. Can. Field-Nat. 109(2): 143–171.<br />
Chen, P.-c. 1941. Studien ber die ostasiatischen Arten<br />
der Pottiaceae, I–II. Hedwigia 80: 1–76; 141–<br />
322.<br />
Churchill, S. P. 1989. Bryologia Novo Granatensis.<br />
Estudios de los musgos de Colombia. Tropical<br />
Bryology 1: 95–132.<br />
Churchill, S. P. & E. L. Lina<strong>re</strong>s C. 1995. Prodromus<br />
Bryologiae Novo-Granatensis. Instit. Cienc.<br />
Nat., Mus. Hist. Nat. Bibliot. "Jose Jeronimo<br />
Triana" 12. 2 Vols.
Crum, H. A. & L. E. Anderson. 1958. Taxonomic<br />
studies in North American mosses. VI-XIII. J.<br />
<strong>of</strong> the Elisha Mitchell Sci. Soc. 74: 32.<br />
Crum, H. A. & L. E. Anderson. 1981. 2 Vols. Mosses <strong>of</strong><br />
Eastern North America. Columbia University<br />
P<strong>re</strong>ss, New York.<br />
Crum, H. A. & E. B. Bartram. 1958. A Survey <strong>of</strong> the<br />
Moss Flora <strong>of</strong> Jamaica. Institute <strong>of</strong> Jamaica,<br />
Science Series Bulletin 8.<br />
Crum, H. A. & W. C. Stee<strong>re</strong>. 1957. Scientific Survey <strong>of</strong><br />
Porto Rico and the Virgin Islands Vol. VII.<br />
Park 4. New York Academy <strong>of</strong> Sciences.<br />
Crum, H. A. & W. C. Stee<strong>re</strong> & L. E. Anderson. 1973. A<br />
new list <strong>of</strong> mosses <strong>of</strong> North America, north <strong>of</strong><br />
Mexico. Bryologist 76: 85–130.<br />
Crundwell, A. C. & E. Nyholm. 1962. Notes on the<br />
genus Tortella. I. T. inclinata, T. densa, T.<br />
flavovi<strong>re</strong>ns and T. gla<strong>re</strong>icola. Trans. Brit.<br />
Bryol. Soc. 4: 187–193.<br />
Crundwell, A. C. & E. Nyholm. 1963. Notes on the<br />
genus Tortella. II. Tortella arctica. Bryologist<br />
66: 184–191.<br />
Delgadillo M., C., B. Bello & A. C rdenas. 1995.<br />
LATMOSS: A Catalogue <strong>of</strong> Neotropical<br />
Mosses. Monographs in Systematic Botany<br />
from the <strong>Missouri</strong> <strong>Botanical</strong> <strong>Garden</strong> 56: 1–191.<br />
Dema<strong>re</strong>t, F. & E. Castagne. 1964. Flo<strong>re</strong> Generale de<br />
Belgique. Bryophytes. Vol. 2, Fascicle 3.<br />
Ministe<strong>re</strong> de L'Agricultu<strong>re</strong>, Jardin Botanique<br />
de L'Etat. Bruxelles.<br />
Dixon, H. N. 1924. The Student's Handbook <strong>of</strong> British<br />
Mosses. London.<br />
Dixon, H. N. 1930. Additions to the Moss Flora <strong>of</strong> the<br />
North-Western Himalayas. Annal. Bryol. 3:<br />
51–70.<br />
Düll, R. 1984. Distribution <strong>of</strong> the European and<br />
Macaronesian Mosses (Bryophytina). Part I.<br />
Bryologische Beitr„ge Vol. 4. I. Düll-<br />
Hermanns Verlag. Rheurdt, Germany.<br />
Düll, R. 1992. Distribution <strong>of</strong> the European and<br />
Macaronesian Mosses (Bryophytina)<br />
Annotations and Prog<strong>re</strong>ss. Bryologische<br />
Beitr„ge Vol. 8/9. I. Düll-Hermanns Verlag.<br />
Düll, R. & L. Meinunger. 1989. Deutschlands Moose.<br />
IDH Verlag, Bad M nste<strong>re</strong>ifel Ohlerath.<br />
Eckel, P. M. 1991. Tortella tortelloides (Musci:<br />
Pottiaceae) new to North America. Bryologist<br />
94: 84–87.<br />
Eckel, P. M. 1996. Trichostomum tenuirost<strong>re</strong> var.<br />
gemmiparum (Schimp.) Zand. new to Japan.<br />
Bryologist 99(4): 460.<br />
Eckel, P. M. 1997. The moss Tortella alpicola new to<br />
Alberta and the Yukon Territory with a<br />
discussion <strong>of</strong> its range and comments on<br />
<strong>re</strong>lated species. Can. Field-Nat. 3: 320–322.<br />
Eckel, P. M. 1997. Tortella knightii, an Australasian<br />
species new to South America in Tierra del<br />
Fuego. Bryologist 100(2): 210–211.<br />
Fife, A. J. 1984. Records <strong>of</strong> new or otherwise<br />
inte<strong>re</strong>sting mosses in New Zealand, including a<br />
50<br />
new species <strong>of</strong> Racomitrium. New Zealand<br />
Journal <strong>of</strong> Botany 22: 1–6.<br />
Fife, A. J. 1995. Checklist <strong>of</strong> the mosses <strong>of</strong> New<br />
Zealand. Bryologist 98(3): 313–337.<br />
Flowers, S. 1973. Mosses: Utah & the West. Brigham<br />
Young Univ. P<strong>re</strong>ss, Provo, Utah.<br />
Gove, P. B., ed. & editorial staff. 1976. Webster's Third<br />
New International Dictionary <strong>of</strong> the English<br />
Language Unabridged. G. & C. Merriam Co,<br />
Springfield, Mass.<br />
Haring, I. M. 1938. Tortella. In A. J. Grout, Moss Flora<br />
<strong>of</strong> North America. I(3): 165–170. Newfane,<br />
Vermont.<br />
Hilpert, F. 1933. Studien zur Systematik der<br />
Trichostomaceen. D<strong>re</strong>sden.<br />
Hoe, W. J. 1974. Annotated checklist <strong>of</strong> Hawaiian<br />
mosses. Lyonia 1: 1–45.<br />
Holmg<strong>re</strong>n, P. K., N. H. Holmg<strong>re</strong>n & L. C. Barnett.<br />
1990. Index Herbariorum. Part 1. Edition 8.<br />
New York <strong>Botanical</strong> <strong>Garden</strong>, Bronx, New<br />
York.<br />
Hyvönen, J. 1991. Tortella fragilis (Pottiaceae) <strong>re</strong>ported<br />
for southern South America. Bryologist 94:<br />
416–418.<br />
Ignatov, M. S. & O. M. Afonina. 1992. Check-list <strong>of</strong> the<br />
Mosses <strong>of</strong> the Former USSR. Arctoa 1: 1–85.<br />
I<strong>re</strong>land, R. R. 1982. Moss Flora <strong>of</strong> the Maritime<br />
Provinces. National Museums <strong>of</strong> Canada<br />
Publications in Botany 13. Ottawa.<br />
I<strong>re</strong>land, R. R., G. R. Brassard, W. B. Sch<strong>of</strong>ield & D. H.<br />
Vitt. 1987. Checklist <strong>of</strong> the mosses <strong>of</strong> Canada<br />
II. Lindbergia 13: 1–62.<br />
Juratzka, J. 1882. Die Laubmossflora von Öster<strong>re</strong>ich-<br />
Ungarn, J. B<strong>re</strong>idler & J. B. Förster, eds.<br />
Vienna.<br />
Ketchledge, E. H. 1957. Checklist <strong>of</strong> the Mosses <strong>of</strong><br />
New York State. New York State Museum<br />
Bull. 363. State Education Department,<br />
Albany, New York.<br />
Ketchledge, E. H. 1980. Revised Checklist <strong>of</strong> the<br />
Mosses <strong>of</strong> New York State. New York State<br />
Museum Bull. 440, R. S. Mitchell, ed. State<br />
Education Department, Albany, New York.<br />
Kindberg, N. C. 1897. Species <strong>of</strong> European and N.<br />
American Bryineae (Mosses. Vol.2, Part 2.<br />
Linköping, Sweden.<br />
Kramer, W. 1980. Tortula Hedw. sect. Rurales De. Not.<br />
(Pottiaceae, Musci) in der Ostlicher Holarktis.<br />
Cramer, Vaduz.<br />
Lange, M. T., Pr„st: Toscanske Mosser, et bryologisk<br />
Bidrag. Botanisk Tidsskrift, Copenhagen, 2:<br />
226–254.<br />
Latzel, A. 1934. Beitrag zur Kenntnis der Moose des<br />
Komitats Baranya. Magyar botanikai lapok.<br />
Ungarische botanische Blätter. 33: 160–191.<br />
Limpricht, K. G. 1890. Die Laubmoose Deutschlands,<br />
Öster<strong>re</strong>ichs und der Schweiz. 1: 1–836.<br />
Leipzig.<br />
Macoun, J. & N. C. Kindberg. 1892. Catalogue <strong>of</strong><br />
Canadian Plants. Part. VI. Musci. Geological
and Natural History Survey <strong>of</strong> Canada.<br />
Mont<strong>re</strong>al.<br />
Magill, R. E. 1981. Bryophyta. Part 1 Mosses. Fascicle<br />
1. Sphagnaceae-Grimmiaceae. In O. A.<br />
Leistner (ed.), Flora <strong>of</strong> Southern Africa.<br />
P<strong>re</strong>toria.<br />
Matteri, C. M. 1985. Catálogos de las briófitas.<br />
Catálogo de los musci: 265–298. In O.<br />
Boelcke, D. M. Moo<strong>re</strong> & F. A. Roig (eds.), La<br />
Transecta Botánica de Patagonia austral.<br />
Consejo nacional de Investigaciones<br />
Cientificas y Ténicas (Argentina), Instituto de<br />
la Patagonia (Chile), Royal Society (Gran<br />
B<strong>re</strong>taña). Buenos Ai<strong>re</strong>s.<br />
Matteri, C. M. 1986. Overview <strong>of</strong> the phytogeography<br />
<strong>of</strong> the moss flora from southern Patagonia, at<br />
51°–52° South Latitude. J. Hattori Bot. Lab.<br />
60: 171–174.<br />
May, R. 1986. Notes on some Macaronesian Tortella<br />
species. Bryologische Beiträge, R. Dull, ed.,<br />
Duisberg. 6: 58–66.<br />
McIntosh, T. T. 1986. The Bryophytes <strong>of</strong> the Semi-Arid<br />
Steppe <strong>of</strong> South-Central British Columbia.<br />
Dissert., University <strong>of</strong> British Columbia,<br />
Vancouver, B.C., Canada.<br />
Meylan, Ch. 1921. Nouvelles contributions a la flo<strong>re</strong><br />
bryologique du Jura. Rev. Bryol. 48: 1–5.<br />
Miller, N. G. 1973. Lateglacial plants and plant<br />
communities in northwestern New York State.<br />
J. Arnold Arbo<strong>re</strong>tum. 54: 123–159.<br />
Miller, N. G. 1976. Quaternary fossil bryophytes in<br />
North America: a synopsis <strong>of</strong> the <strong>re</strong>cord and<br />
some phytogeographic implications. J. Hattori<br />
Bot. Lab. 41: 73–85.<br />
Mitten, W. 1868. New or ra<strong>re</strong> British mosses. J. Bot.<br />
London. 6: 97–99, plate 77.<br />
Mönkemeyer, W. 1927. Die Laubmoose Europas. Vol.<br />
4. In L. Rabenhorst, Kryptogamenflora von<br />
Deutschland, Öster<strong>re</strong>ich und der Schweiz.<br />
Leipzig.<br />
Muller, Karl. 1878–79. Prodromus Bryologiae<br />
Argentinicae. I. Linnaea 42: 217–460.<br />
Noguchi, A. 1988. Illustrated Moss Flora <strong>of</strong> Japan. Part<br />
2. Hattori <strong>Botanical</strong> Laboratory, Obi,<br />
Nichinan-shi.<br />
Nyholm, E. 1956. Illustrated Moss Flora <strong>of</strong><br />
Fennoscandia. II. Musci. Fasc. II. Gleerups,<br />
Lund, Sweden.<br />
Nyholm, E. 1989. Illustrated Flora <strong>of</strong> Nordic Mosses.<br />
Fasc. 2. Pottiaceae—Splachnaceae—<br />
Schistostegaceae. Nordic Bryological Society.<br />
Copenhagen. Paul, H. 1943. Nachträge und<br />
Bermerkungen zur Moosflora Beyerns. Ber.<br />
Bayer. Bot. Ges. 26: 118–133.<br />
Persson, H. 1947. Bryum arcticum och några andra<br />
mossfynd från Stora Karlsö. Svensk Bot.<br />
Tidskr. 41, I: 141–150.<br />
Persson, H. & W. A. Weber. 1958. The bryophyte flora<br />
<strong>of</strong> Mt. McKinley National Park, Alaska.<br />
Bryologist, 61: 214–42.<br />
51<br />
Pilous, Z. 1965. Fragmenta bryologica 56. Tortella<br />
rigens Albertson und Tortella densa Crund. et<br />
Nyh., zwei neue tschechoslowakische Moose.<br />
P<strong>re</strong>slia 37: 20–22.<br />
Podpera, J. 1954. Conspectus Muscorum Europaeorum.<br />
Nakladatelstvi Ceskoslovenske Akademie Ved<br />
Praha.<br />
Polunin, N. 1947. Botany <strong>of</strong> the Canadian Eastern<br />
Arctic. Part II Thallophyta and Bryophyta.<br />
Canada Department <strong>of</strong> Mines and Resources,<br />
National Museum <strong>of</strong> Canada Bull. 97,<br />
Biological Series 26.<br />
Redfearn, P. L., Jr. 1969. Bryophytes <strong>of</strong> the Interior<br />
Highlands XIV. Tortella mollissima new to<br />
North America. Bryologist 72: 60.<br />
Redfearn, P. L., Jr. 1993. List <strong>of</strong> Mosses <strong>of</strong> China. Flora<br />
Online (Buffalo Museum <strong>of</strong> Science, Buffalo,<br />
NY.) 29 (ver.1.0). Reimers, H. 1951. Beiträge<br />
zur Kenntnis der Bunten Erdflechten-<br />
Gesellschaft. I.–II. Ber. deutsch. bot. Ges. 63:<br />
147–156<br />
Renauld, F. & J. Cardot. New mosses <strong>of</strong> North America.<br />
II. Bot. Gaz. 14(4): 91–100.<br />
Robinson, H. E. 1972. Observations on the origin and<br />
taxonomy <strong>of</strong> the Antarctic moss flora. In G. A.<br />
Llano (ed.), Antarctic Ter<strong>re</strong>strial Biology,<br />
Antarctic Research Ser. 20: 163–177.<br />
American Geophysical Union, Washington,<br />
D.C.<br />
Rubers, W. 1973. [In Dutch]. Enkele opmerkingen over<br />
Nederlandse Tortella's. Lindbergia 2: 128–129.<br />
Sainsbury, G. O. K. 1955. A handbook <strong>of</strong> the New<br />
Zealand mosses. Royal Society <strong>of</strong> New<br />
Zealand Bull.5: 1–490.<br />
Saito, K. 1975. A Monograph <strong>of</strong> Japanese Pottiaceae<br />
(Musci). J. Hattori Bot. Lab. 39: 373–537.<br />
Savicz-Ljubitzkaja, L. I. & Z. N. Smirnova. 1970.<br />
[Handbook <strong>of</strong> the Mosses <strong>of</strong> the U.S.S.R. The<br />
acrocarpous mosses.] Acad. Sci. USSR,<br />
Komarov <strong>Botanical</strong> Institute, Leningrad. [text<br />
in Russian].<br />
Schimper, W. P. 1855. Corollarium Bryologiae<br />
Europaeae, Conspectum Diagnosticum<br />
Familiarum, Generum et Specierum. Stuttgart.<br />
Sch<strong>of</strong>ield, W. B. 1965. Cor<strong>re</strong>lations between the moss<br />
floras <strong>of</strong> Japan and British Columbia, Canada.<br />
J. Hattori Bot. Lab. 28: 17–42<br />
Seki, T. 1974. A moss flora <strong>of</strong> Provincia de Ais‚n,<br />
Chile. Results <strong>of</strong> the second scientific<br />
expedition to Patagonia by Hokkaido and<br />
Hiroshima Universities, 1967. J. Sci.<br />
Hiroshima Univ. Ser. B, Div. 2 (Bot.) 15: 9–<br />
101.<br />
Sharp, A. J., H. Crum & P. M. Eckel, eds. 1994. Moss<br />
Flora <strong>of</strong> Mexico. Mem. New York Bot. Gard.<br />
69. 2 vols.<br />
Smith, A. J. E. 1978. The Moss Flora <strong>of</strong> Britain and<br />
I<strong>re</strong>land. Cambridge University P<strong>re</strong>ss,<br />
Cambridge.
Stafleu, A. & R. S. Cowan. 1981. Taxonomic literatu<strong>re</strong>.<br />
Vol. III: Lh–O. ed. 2. The Hague, Ut<strong>re</strong>cht.<br />
Stee<strong>re</strong>, W. C. 1939. Tortula, pp. 228–246 In A. J. Grout<br />
(ed.), Vol.I, Moss Flora <strong>of</strong> North America<br />
north <strong>of</strong> Mexico. Published by the author,<br />
Newface, Vermont.<br />
Stee<strong>re</strong>, W. C. 1940. Tortula in North America north <strong>of</strong><br />
Mexico. Bryologist 43: 12–23, 45–56, 76–86,<br />
98–109.<br />
Stee<strong>re</strong>, W. C. 1976. Ecology, phytogeography and<br />
floristics <strong>of</strong> arctic Alaskan bryophytes. J.<br />
Hattori Bot. Lab. 41:47–72.<br />
Stee<strong>re</strong>, W. C. 1978. The Mosses <strong>of</strong> Arctic Alaska. J.<br />
Cramer. Vaduz.<br />
Stee<strong>re</strong>, W. C. & G. W. Scotter. 1978. Additional<br />
bryophytes from Nahanni National Park and<br />
vicinity, Northwest Territories, Canada. Canad.<br />
J. Bot. 56: 234–244.<br />
Townsend, C. C. 1965. Bryophytes from Cyprus. Rev.<br />
Bryol. et Lich‚nol. NS 33: 484–493.<br />
Van der Wijk, R., W. D. Margadant & P. A. Florsch tz.<br />
1959–1969. Index Muscorum. Reg. Veg. Vols.<br />
17, 26, 33, 48, 65.<br />
Vitt, D. H. 1974. A key and synopsis <strong>of</strong> the mosses <strong>of</strong><br />
Campbell Island, New Zealand. New Zealand<br />
J. Bot. 12: 185–210.<br />
Wa<strong>re</strong>ham, R. T. 1939a. Pottia. In A. J. Grout, Moss<br />
Flora <strong>of</strong> North America North <strong>of</strong> Mexico. 1(4):<br />
197–208.<br />
Weber, W. A. 1973. Guide to the Mosses <strong>of</strong> Colorado.<br />
Institute <strong>of</strong> Arctic and Alpine Research,<br />
University <strong>of</strong> Colorado, Occ. Paper 6.<br />
Williams, C. 1968. New and additional moss <strong>re</strong>cords for<br />
Ontario. Bryologist Vol.71: 282–284.<br />
52<br />
Zander, R. H. 1977. The tribe Pleuroweisieae<br />
(Pottiaceae, Musci) in Middle America.<br />
Bryologist 80: 233–269.<br />
Zander, R. H. 1978. A propaguliferous variant <strong>of</strong><br />
Oxystegus tenuirostris in Europe, India,<br />
Mexico, Cuba and Brazil. Lindbergia 4(3–4):<br />
285–288.<br />
Zander, R. H. 1993. Genera <strong>of</strong> the Pottiaceae: Mosses <strong>of</strong><br />
Harsh Environments. Bull. Buffalo Soc. Nat.<br />
Sci. 32.<br />
Zander, R. H. 1994a. Bryoerythrophyllum, pp. 273–283.<br />
In A. J. Sharp, H. A. Crum and P. M. Eckel<br />
(eds.), Moss Flora <strong>of</strong> Mexico. Mem. New York<br />
Bot. Gard. 69. 2 vols.<br />
Zander, R. H. 1994b. Oxystegus, pp. 233–235. In A. J.<br />
Sharp, H. A. Crum and P. M. Eckel (eds.),<br />
Moss Flora <strong>of</strong> Mexico. Mem. New York Bot.<br />
Gard. 2 vols.<br />
Zander, R. H. 1994c. St<strong>re</strong>ptocalypta, pp. 238–242. In A.<br />
J. Sharp, H. A. Crum and P. M. Eckel (eds.),<br />
Moss Flora <strong>of</strong> Mexico. Mem. New York Bot.<br />
Gard. 69. 2 vols.<br />
Zander, R. H. 1994d. Tortella, pp. 235–238. In A. J.<br />
Sharp, H. A. Crum and P. M. Eckel (eds.),<br />
Moss Flora <strong>of</strong> Mexico. Mem. New York Bot.<br />
Gard. 69. 2 vols.<br />
Zander, R. H. 1997. Merceyoideae and<br />
Trichostomoideae. In G. S. Mogensen (ed.),<br />
Illustrated Moss Flora <strong>of</strong> Arctic North America<br />
and G<strong>re</strong>enland. Meddel om Groenland,<br />
Bioscience (in p<strong>re</strong>ss).<br />
Zander, R. H. & W. J. Hoe. 1979. Geographic<br />
disjunction and heterophylly in Tortella<br />
fragilis var. tortelloides (= Sarconeurum<br />
tortelloides). Bryologist 82: 84–87.<br />
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PLATES 1–11 FOLLOW
Plate 1. Tortella humilis. 1. Habit, wet and dry, short (typical) form. 2. Habit, wet and dry, elongate<br />
(japonica) form from British Columbia. 3. Stem cross section. 4. Five leaves from typical populations, central U.S.<br />
5. Four leaves from elongate populations, Texas. 6. Four leaves from elongate populations (as Tortella japonica),<br />
Japan. 7. Four leaves from elongate populations, Mexico. 8. Two leaves <strong>of</strong> elongate, robust specimen from Ontario.<br />
9. Five elongate, robust leaves from single stem, the type (at PC) <strong>of</strong> Tortella japonica, Japan. 10. Leaf apex. 11.<br />
Leaf cross sections, lower median to leaf apex. 12, 12. Stalked perigonial buds, two single, one double. 13.<br />
Sporophyte and calyptra. 14. Sporophyte and operculum. 15. Capsule and peristome.<br />
53
Plate 2. Tortella flavovi<strong>re</strong>ns. 1. Habit, wet and dry. 2. Stem cross section. 3. Four stem leaves. 4. Leaf cross<br />
section series from lower middle to apical <strong>re</strong>gion. 5. Leaf apex. 6. Leaf base. 7. Perichaetial leaves and base <strong>of</strong> seta.<br />
8. Two outer perichaetial leaves. 9. Peristome.<br />
54
Plate 3. Tortella alpicola. 1. Sterile habit, wet and dry. 2. Fertile habit, wet. 3. Stem cross section. 4. Six<br />
leaves. 5. Distal leaf margin showing scalloped indentations. 6. Leaf base. 7. Th<strong>re</strong>e cross sections <strong>of</strong> sterile stem<br />
leaves. 8. Th<strong>re</strong>e cross sections <strong>of</strong> fertile stem leaves. 9. Th<strong>re</strong>e views <strong>of</strong> propagula formation at stem apex. 10. Th<strong>re</strong>e<br />
examples <strong>of</strong> propagula, including apex. 11. Five perichaetial leaves.<br />
55
Plate 4. Tortella tortuosa var. tortuosa. 1. Habit, wet and dry <strong>of</strong> perichaetiate plant, showing diffe<strong>re</strong>ntiated<br />
perichaetial leaves. 2. Stem cross section 3. Eight leaves showing variation in size and <strong>re</strong>curvatu<strong>re</strong>. 4. Youngest<br />
leaves at stem apex showing long mucro emergent. 5. Leaf apex. 6. Leaf base. 7. Leaf cross sections from medial to<br />
distal <strong>re</strong>gion. 8. Perigonium and leaves. 9. Perichaetial leaves. 10. A<strong>re</strong>olation <strong>of</strong> some perichaetial leaves showing<br />
extensive border <strong>of</strong> smooth, elongate cells.<br />
56
Plate 5. Tortella tortuosa var. arctica. 1. Habit, wet and dry. 2. Stem cross section. 3. Five stem leaves. 4.<br />
Leaf base. 5,5. Leaf cross sections. 6. Marginal cells at junction <strong>of</strong> proximal cells and distal laminal cells. 7.<br />
Perichaetium. 8. Perichaetial leaf.<br />
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Plate 6. Tortella tortuosa var. fragilifolia. 1. Habit, dry. 2. Stem cross section with central strand. 3. Seven<br />
stem leaves. 4. Marginal cells. 5. Leaf cross sections from various specimens showing various aberrations: bistratose<br />
juxtacostal a<strong>re</strong>as (f<strong>re</strong>quently asymmetrical), bistratose patches, loss <strong>of</strong> ventral ste<strong>re</strong>id toward the leaf apex and<br />
undiffe<strong>re</strong>ntiated costa. 6. Apex <strong>of</strong> fertile stem, Quebec specimen. 7. Perichaetial leaves.<br />
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Plate 7. Tortella fragilis. 1. Habit, wet and dry. 2. Habit <strong>of</strong> <strong>re</strong>duced stem, Quebec. 3. Stem cross section. 4.<br />
Two subapical stem leaves. 5. Leaves at stem apex showing emergent propaguloid apex. 6. Th<strong>re</strong>e leaves not forming<br />
propagula, from branch innovations. 7. Th<strong>re</strong>e leaves <strong>of</strong> <strong>re</strong>duced stem, Quebec. 8. Emergent propaguloid leaf at stem<br />
apex in <strong>re</strong>duced plant, Quebec. 9. Apex <strong>of</strong> propaguloid leaf. 10. Two apices <strong>of</strong> non-propaguloid branch innovation<br />
leaves. 11. Distal margin showing smooth marginal border <strong>of</strong> elongate cells. 12. Seven leaf cross-sections from<br />
median to apical (propaguloid) <strong>re</strong>gions.<br />
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Plate 8. Tortella inclinata var. inclinata (1–10). 1. Habit, wet and dry. 2. Habit showing apical whorl. 3.<br />
Stem cross section. 4. Five leaves. 5. Leaf apex. 6. Elongate cells on the ventral surface <strong>of</strong> the costa in surface view.<br />
7. Four leaf cross sections. 8. Apical portion <strong>of</strong> fertile stem. 9. Capsule. 10. Inner perichaetial leaves. Tortella<br />
rigens (11–13): Ohio and New York plants. 11. Th<strong>re</strong>e leaves from New York specimen. 12. Th<strong>re</strong>e leaves from Ohio<br />
specimen. 13. Leaf apex, Ohio specimen.<br />
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Plate 9. Tortella inclinata var. densa. 1. Habit, wet, showing maturing leafy lateral shoot. 2. Stem apex,<br />
dry. 3. Stem cross section. 4. Eight stem leaves. 5. Leaf cross sections. 6. Leaf apex. 7. Lateral shoot with primordial<br />
leaves. 8. Perichaetium. 9. Dissected perichaetium showing perichaetial leaves and archegonia. 10. Th<strong>re</strong>e leaves<br />
with narrowly acute apices.<br />
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Plate 10. Tortella rigens: European specimens. 1. Habit, wet and dry. 2. Stem cross section. 3. Stem leaves,<br />
showing variation from short, cucullate-leaved forms to variously acuminate forms with diffe<strong>re</strong>ntiated apical<br />
<strong>re</strong>gions. 4. Two leaf apices. 5. Cells at midleaf. 6. Leaf cross sections showing bistratose juxtacostal a<strong>re</strong>as and<br />
broadly channeled aspect.<br />
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Plate 11. Tortella nitida: all figu<strong>re</strong>s a<strong>re</strong> drawn from Lindberg's type (sterile) at S except whe<strong>re</strong> noted, see<br />
text. 1. Habit, wet and dry. 2. Stem cross section. 3. Stem leaves. 4. Leaf <strong>of</strong> var. irrigata, stippled a<strong>re</strong>a showing<br />
<strong>re</strong>gion <strong>of</strong> quadrate, papillose cells on the back <strong>of</strong> the costa and two p<strong>re</strong>sumably deciduous apices from leaves on the<br />
same stem (non-type). 5. Two leaf apices, side view. 6. Leaf apex, front view. 7. Leaf apex <strong>of</strong> "var. acuminata"<br />
(non-type, see text). 8. Leaf base. 9. Stem leaf cross sections from median <strong>re</strong>gion to near apex. 10. Perichaetial<br />
leaves and base <strong>of</strong> seta (non-type). 11. Capsules operculate and deoperculate (non-type). 12. Peristome (non-type).<br />
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