33. BARBULA Plates 43 Plate 44. Plate 45.

Barbula Hedw., Spec. Musc. 115, 1801, nom. cons. non Loureiro, 1790. Lectotype: Barbula unguiculata Hedw.

Barbiferus Poir., Enc. Meth. Bot. Suppl. 1(2): 587, 1811, nom. illeg.

Mollia Schrank. ex Lindb., Utkast Nat. Grupp. Eur. Bladmoss. 38, 1878, hom. illeg. incl. gen. prior. non Mollia Gmell., 1791, nec Mollia, 1806, nec Mollia Mart., 1826, nom. cons. (p.p. Barbula Hedw. et p.p. Tortula Hedw.).

Sect. Barbula

Tortula subg. Barbula (Hedw.) De Not., Mem. R. Acc. Sc. Torino 40: 287, 1838.

Barbula subg. Barbula Schimp., Coroll. 31, 1856.

Barbula subg. Helicopogon (Mitt.) Lindb., Musci Scand. 22, 1879, nom. illeg. incl. typ. gen.

Barbula subg. Eubarbula (C. Müll.) Kindb., Eur. N. Amer. Bryin. 2: 246, 1897, nom. illeg.

Barbula subg. Tortobarbula Szafr., Fl. Polska Mchy 1: 213, 1957 [1958] nom. inval. descr. polon.

Bryum sect. Barbula (Hedw.) Relh., Fl. Cantabr. ed. 2: 426, 1802.

Barbula sect. Barbula Rebent., Prod. Fl. Neomarch. 257, 1804, nom. illeg.

Barbula sect. Caulescentes Hüb., Musc. Germ. 317, 1833, nom. nud. incl. typ. gen.

Tortula sect. Unguiculatae De Not., Mem. R. Acc. Sc. Torino 40: 287, 1838. Type: Barbula unguiculata Hedw.

Barbula sect. Unguiculatae BSG, Bryol. Eur. 2: 80, 1842 (fasc. 13–15 Mon. 18), nom. illeg. incl. typ. gen.

Barbula sect. Senophyllum C. Müll., Syn. 1: 606, 1849 [Not an error for "steno‑", see protologue of Pottia sect. Senophyllaria C. Müll.]

Barbula sect. Eubarbula C. Müll., Syn. 1: 623, 1849, nom. illeg. excl. typ. gen. cons.

Tortula sect. Barbula (Hedw.) Mitt., J. Linn. Soc. Bot. 12: 144, 158, 1869.

Tortula sect. Helicopogon Mitt., J. Linn. Soc. Bot. 12: 142, 150, 1869.

Barbula sect. Falax Lzaro é Ibiza, Bot. Descr. Comp. Fl. Esp. 1: 586, 1869, nom. illeg. incl. typ. gen. cons.

Barbula sect. Eubarbula Lindb. ex Braithw., Brit. Moss Fl. 1: 261, 1887, nom. illeg. excl. typ. gen. cons.

Barbula sect. Helicopogon (Mitt.) Braithw., Brit. Moss. Fl. 1: 274, 1887.

Barbula sect. Senophyllum C. Müll. ex Podp., Consp. Musc. Eur. 200, 1954.

Sect. Hyophiladelphus C. Müll., Syn. 1: 604, 1849.

Barbula subg. Hyophiladelphus (C. Müll.) Zand., Phytologia 44: 201, 1979. Lectotype: Barbula agraria Hedw. fide Zander, Phytologia 44, 201, 1979.

Tortula sect. Hyophiladelphus (C. Müll.) Broth., Nat. Pfl. 1(3): 429, 1902.

Barbula sect. Agrariae Steere in Grout, Moss Fl. N. Amer. 1(3): 173, 1938, nom. illeg. Type: Barbula agraria Hedw.

Sect. Bulbibarbula C. Müll., Flora 62: 379, 1879.

Barbula sect. Rhystobarbula C. Müll., Gen. Musc. Fr. 463, 1900, nom. illeg. incl. sect. prior.

Tortula sect. Rhystobarbula Dix., J. Bot. 80: 41, 1941.

Tortula sect. Bulbibarbula (C. Müll.) Wijk & Marg., Taxon 7: 290, 1958. Type: Tortula eubryum C. Müll.

Sect. Convolutae B.&S. in BSG, Bryol. Eur. 2: 91, 1842 (fasc. 13–15 Mon. 29).

Streblotrichum P. Beauv., Mag. Enc. 5: 317, 1804. Lectotype: Streblotrichum convolutum (Hedw.) P. Beauv. fide Saito, J. Hattori Bot. Lab. 39: 499, 1975.

Tortula sect. Convolutae De Not., Mem. R. Acc. Sc. Torino 40: 287, 1838. Type: Tortula convoluta (Hedw.) Gaertn., Meyer & Scherb.

Tortula sect. Leptopogon Mitt., J. Linn. Soc. Bot. 12: 143, 156, 1869. Type: Tortula calyculosa Mitt., lectotyp. nov.

Tortula subg. Streblotrichum (P. Beauv.) Chev., Fl. Gen. Env. Paris 2: 51, 1827.

Barbula subg. Odontophylla Saito, J. Hattori Bot. Lab. 39: 499, 1975. Type: Barbula hiroshii Saito.

Barbula sect. Leptopogon (Mitt.) Lindb., Musc. Scand. 22, 1879.

Barbula subg. Streblotrichum (P. Beauv.) Limpr., Laubm. Deutschl. 1: 626, 1888.

Sect. Hydrogonium (C. Müll.) Saito, J. Hattori Bot. Lab. 39: 492, 1975.

Hydrogonium (C. Müll.) Jaeg., Ber. St. Gall. Naturw. Ges. 1877–78: 405, 1880 (Ad. 2: 669). Lectotype: Hydrogonium ehrenbergii (Lor.) Jaeg. fide Saito, J. Hattori Bot. Lab. 39: 492, 1975.

Didymodon subg. Hydrogonium (C. Müll.) Kindb., Eur. N. Amer. Bryin. 2: 273, 1897.

Barbula subg. Hydrogonium (C. Müll.) Fleisch., Musci Fl. Buitenzorg 1: 352, 1904.

Trichostomum sect. Hydrogonium C. Müll., Linnaea 40: 297, 1876.

Semibarbula Herz. ex Hilp., Beih. Bot. Zentralbl. 50: 626, 1933. Type: Semibarbula indica (Hook.) Hilp.

Hydrogonium sect. Barbuliella Chen, Hedwigia 80: 233, 1941.

Hydrogonium sect. Euhydrogonium Chen, Hedwigia 80: 233, 1941, nom. illeg.

Sect. Pachynoma (Mitt.) Par., Ind. Bryol. ed. 2, 3: 348, 1905.

Tortula sect. Pachynoma Mitt., J. Linn. Soc. Bot. 12: 143, 151, 1869.

Sect. Pseudocrossidiella Thér. in Felipp., Rev. Bryol. n. ser. 2: 216, 1930. Type: Barbula subgrimmiacea Thér.

Subsect. Purpureaeformes Kindb., Eur. N. Amer. Bryin. 2: 246, 1897. Type: Barbula purpurea C. Müll.

Plants loosely caespitose or forming cushions, yellowish brown, brown or blackish above, yellowish brown to reddish brown below. Stems branching irregularly, ca. 0.2–3.0 cm in length, transverse section rounded-pentagonal or irregular, central strand present or seldom absent, sclerodermis usually present, hyalodermis occasionally present; axillary hairs 2–10 cells in length, usually all hyaline, occasionally basal 1–2 cells firm-walled; rhizoids sparse to common. Leaves appressed-incurved to weakly spreading, often contorted or twisted about stem and occasionally catenulate when dry, spreading when moist, spathulate, ligulate or more usually broadly lanceolate to long-triangular, usually ca. 1–3 mm in length, upper lamina usually deeply and narrowly grooved ventrally along costa, occasionally only broadly concave, lamina unistratose or seldom bistratose in patches, margins usually recurved in lower 1/2–2/3 of leaf, occasionally plane, entire or occasionally denticulate near apex or above midleaf, seldom dentate, margins occasionally thick-walled, seldom bi- or multistratose; apex rounded to obtusely acute, usually mucronate, occasionally entire or short-apiculate; base usually weakly differentiated to ovate, sometimes broadened and sheathing, sometimes narrowly decurrent; costa percurrent to short-excurrent as a sharp mucro, seldom short-awned, occasionally ending a few cells below the apex, superficial cells elongate or occasionally quadrate to short-rectangular ventrally, usually elongate but sometimes quadrate to short-rectangular dorsally, 2–3(–5) rows of cells across costa ventrally at midleaf, costal transverse section oval to semicircular, two stereid bands usually present, usually small but distinct ventrally, usually strong dorsally and crescent-shaped but sometimes nearly semicircular, epidermis usually differentiated ventrally, usually present but weakly differentiated dorsally, guide cells usually 2–4 in 1 layer, hydroid strand occasionally present; upper laminal cells quadrate to short-rectangular, 6–13 µm in width, usually 1:1, walls thin to evenly thickened, usually superficially bulging on both sides, occasionally ventrally bulging and dorsally flat or nearly so; papillae hollow or solid, multifid or bifid, 2–3 per lumen, seldom simple or absent, usually obscuring the lumens, occasionally mamillose ventrally; basal cells usually differentiated, reaching across leaf or reaching higher medially or occasionally marginally, rectangular, usually little wider than upper laminal cells, 3–5:1, walls thin to evenly thickened. Propagula when present borne on basal rhizoids or axillary on stalks, often rather large, 30–300 µm in length, of 1–50 cells, clavate to ovate, occasionally armed, multicellular, green to reddish. Dioicous, possibly occasionally rhizautoicous. Perichaetia terminal, inner leaves little differentiated or ovate to long-lanceolate, sometimes strongly sheathing, lower cells long rhomboidal in lower 1/2 of leaf, occasionally to 3/4 or more. Perigonia gemmate, often prominent. Seta 0.5–1.5 cm in length, usually 1 per perichaetium, yellowish to reddish brown, twisted clockwise below, often counterclockwise above; theca usually 0.8–1.5 mm in length, yellowish to reddish brown, ovate to long-cylindrical, exothecial cells rectangular or occasionally rhomboidal, walls thin to evenly thickened, stomates phaneropore, at base of theca, annulus weakly differentiated to strong, of 1–3 rows of vesiculose cells, usually persistent, occasionally revoluble or deciduous in pieces; peristome teeth of 32 narrow rami, seldom short or rudimentary, filamentous to narrowly triangular, usually densely spiculose, with many articulations, usually strongly twisted 1.5 to 2 times counterclockwise, occasionally straight, to 1200 µm in length, basal membrane low but distinct, ca. 40 µm in height, granulate to spiculose. Operculum usually long-conic, ca. 0.8–1.7 mm in length, cells twisted counterclockwise. Calyptra cucullate, smooth, usually 1.5–3.0 mm in length. Spores usually 9–16 µm in diameter, light brown, weakly papillose. Laminal KOH color reaction yellow, occasionally yellowish orange. Reported chromosome number n = 10, 10+m, 11, 12+m, 13, 13+m, 13+2m, 14, 14+2m, 16, 24, 26.

A cosmopolitan genus found in a wide variety of habitats, mainly on soil and acid or calcareous rock.

Saito's (1975a) distinctions between the genera Barbula and Didymodon are to a large extent followed in this treatment. Axillary hair characters, however, are considered here to be more variable than indicated by Saito. In Barbula, the hairs are often but not always entirely much elongate and hyaline (Pl. 44, f. 21—as opposed to the short, basally brown-celled and otherwise hyaline hairs of Didymodon). Some species of Barbula have elongate, entirely hyaline hairs (e.g. B. hiroshii and B. unguiculata), some have firm-walled hair basal cells (e.g. B. riograndensis), and others may be variable within the same species (e.g. B. indica). (Completely hyaline hairs may be interpreted as all firm-walled rather than all thin-walled. Firm-walled basal cells are either hyaline or somewhat more yellowish than the distal cells. The cells of the completely hyaline hairs in Barbula are, in fact, rather firm-walled.) In Didymodon, however, the brownish, firm walls of the basal cells of the axillary hairs appear to develop earlier than they do in those species of Barbula that have them. Small, dark rectangles are generally visible under the microscope through the transparent bases of the leaves of the extreme stem apex of Didymodon species, while they are seldom so evident in Barbula. Careful stripping of the subapical leaves will uncover the young hairs.

Saito's (1975a) use of the shape of the superficial cells of the ventral surface of the costa as a distinction (Barbula with elongate cells—Pl. 44, f. 9, 14, 20, Didymodon sect. Didymodon with short or quadrate cells) is variable for Barbula world wide, though it apparently holds for the Japanese species he revised; Eddy (1990) also considered the elongate ventral costal cells to be taxonomically important in the Malesia area. The two genera, however, can usually be distinguished quickly by the morphology of the laminal papillae and the leaf apex. In Barbula, the upper laminal papillae are rough, knobby, obscuring the lumens, and protuberant along the upper laminal margins (Pl. 43, f. 5), while in Didymodon these are generally low, difficult to distinguish, and little evident along the upper margins. There are, of course, exceptions, notably Barbula sect. Hydrogonium and Didymodon sect. Vineales. Bryoerythrophyllum is quite likeBarbula in papillae morphology but reacts red, not yellow, to KOH. Barbula is unlike Didymodon in that its leaf apex usually ends in an apiculus of one or a few clear cells or in a rather strong, sharp mucro; in Didymodon, the costa ends before or in the apex, or, if excurrent, is rather blunt and opaque, seldom apiculate by one or more clear cells. As Saito (1975a) pointed out, in Barbula the propagula (Pl. 43, f. 20; 44, f. 5, 10) range from small and ovate to large and irregular in shape, while Didymodon has only small ovate propagula. Both Barbula and Didymodon, however, remain rather heterogeneous, and segregate genera will surely be described in the future to include, for instance, such oddities as B. integrifolia and B. eubryum. Compounding this are species of Didymodon still remaining as combinations in Barbula; transfer of some of these is done here, but much remains to be accomplished by revisionists. Barbula may be hypothesized as the start of a reduction series continuing through Barbula sect. Convolutae, Leptobarbula, Gyroweisia and Gymnostomum. Gyroweisia is distinct in the combination of enlarged basal cells, vesiculose and often revoluble annulus, and peristome absent or reduced. It may well be, however, that Barbula will be broken up in the future into segregate genera consisting of narrowly conceived reduction series of species crossing presently recognized limits of these similar genera.

Barbula sect. Convolutae is distinctive in the mostly plane leaf margins, usual presence of a stem hyalodermis, commonly strongly differentiated perichaetial leaves, and generally a yellow seta. It is problematically quite similar to Trichostomum, except for the presence of a twisted peristome, and may be related. However, in many species of sect. Convolutae the basal cells extend farthest up the leaf medially (in others merely straight across) or reaching highest at the midpoint between the costa and the margins on both sides). What is apparently the type of sect. Convolutae, B. convoluta, has a stem section like that of the Merceyoideae (central strand present, comparatively large inner cylinder cells, thin cortex of abruptly smaller stereid cells, hyalodermis little or not differentiated) rather than the Trichostomoideae (central strand variably present, inner cylinder cells often relatively small, cortex commonly of substereid cells, hyalodermis often well differentiated and sometimes in more than one layer). This is also true of B. indica, which, although having plane leaf margins, is clearly a Barbula by its stem anatomy, though probably best placed in Hydrogonium since the generitype of Hydrogonium is clearly a related but derived species. The type of B. cancellata (a name recently much in use in North America) at NY is B. indica var. indica; it bears small propagula. Section Convolutae characteristically has rather large propagula; axillary or rhizoidal propagula are typical of many genera of Barbuleae but are uncommon in genera of Pottieae or Trichostomoideae. It is quite possible, in any case, that upon revision at least certain species of sect. Convolutae (such as B. amplexifolia, Pl. 43, f. 15–20, which has the stem anatomy of the Trichostomoideae) will be seen to better belong in or near Trichostomum, or even Tortella. Norris and Koponen (1989), on the other hand, in their treatment of the bryophytes of an area in New Guinea, indicated that plane-margined Barbula species lack a hyalodermis and have little taper to the costae, while Trichostomum species with which they might be confused have a hyalodermis and tapering costae. Further investigation is necessary at the revision level. They also pointed out that sterile specimens of Hydrogonium can be distinguished from Dicranella (Dicranaceae) by the former's quadrate cells of the ventral surface of the costa and a regular arrangement of the laminal cells in rows.

The genus Tetrapterum is similar to sect. Convolutae in its gametophyte morphology, but differs significantly in the sporophyte. Barbula calycina, which may belong with Tetrapterum, is unusual in its basal cells differentiated into two groups of about equal size, of hyaline, thin-walled, smooth cells towards the margins, and yellow, thick-walled, papillose cells medially. This is reminiscent of a corresponding morphology in Pseudosymblepharis species. Barbula subcalycina has very lax basal cells reminiscent of those of Tortella humilis. Stone (1991) provided good distinctions between B. calycina and B. subcalycina. Barbula calyculosa, B. fendleri and B. fidelis are probably the same as B. convoluta.

Many species of sect. Hydrogonium (the type of which is Barbula ehrenbergii) may have evolved from ancestors quite like B. indica towards a hygric habitat and large size. Barbula leucodontoides (Pl. 44, f. 18–21—isotype, NY!) has a dorsally prorulose costa, and is surely very closely related to B. indica. Other species (e.g. B. zambesiaca) have rather flaccid leaves with reduced papillae and the dorsal surface of the costa is merely bumpy. Barbula javanica, with its ventrally bulging and dorsally smooth (or nearly so) upper lamina, may share ancestors with the Hyophileae. Note that cladistic analysis does not support a close relationship between Hyophila and Barbula, and perhaps the section Hydrogonium should be recognized at the generic level. Barbula agraria (Pl. 43, f. 9–14), with its broad leaves and ventrally bulging upper laminal cells may also belong with the Hyophileae. Both sect. Hydrogonium and sect. Hyophiladelphus have the essentially tropical lowland distribution characteristic of the Hyophileae. Cladistic analysis at the species level might detail support for this possible dismemberment of Barbula along these lines.

Barbula marginatula (Pl. 44, f. 22–25) is at an end point in the evolution of sect. Hydrogonium with the additional character of a cartilaginous, denticulate leaf border of elongate cells. Gangulee (1972) indicated that B. marginatula may represent a “new genus of barbuloid mosses” but if such were recognized the genus should include the types of Hydrogonium and Semibarbula, which clearly belong to the lineage. Barbula pachyloma (refered to Cinclidotus by Hilpert 1933 but recognized as a good species of Barbula by Eddy 1990 and Norris and Koponen 1989) may well belong here too, having multistratose upper laminal borders of stereid cells covered with parenchymatous cells (much like those of Calymperaceae species), but prorulae are not evident; it is much like Dialytrichia in appearance and moist habitat but differs in the stereid cells of the laminal margin, widely channeled (non-keeled) leaves, and quadrate ventral superficial cells of the costa.

Species previously referred to Barbula but which have long-awned, marginally highly revolute leaves with strongly flattened dorsal stereid band and the ventral band often absent, and the perichaetial leaves usually enlarged and convolute-sheathing are better recognized in Pseudocrossidium ((q.v.).

Certain species of Ditrichum, namely D. tortipes (Mitt.) Par. and D. ambiguum Best (cf. Crum & Anderson 1981, Grout 1927 and Robinson 1968—these two species probably conspecific), have once-twisted, densely spiculose peristome teeth and long-triangular, apically rough, setaceous leaves with rectangular, smooth upper laminal cells much like the leaves of forms ofBarbula arcuata. These Ditrichum species may actually belong inBarbula. Future investigation, at least of the B. arcuata complex, should deal with this question. Barbula arcuata differs significantly in the red rather than yellow, more strongly twisted peristome, and the leaves only weakly denticulate and margins unistratose. Its costal section, however, is strikingly like that of the Ditrichum species, especially in the strongly differentiated dorsal epidermal cells.

A quite unusual species is Barbula hispaniolensis (Pl. 44, f. 11–15), which is similar to Bryoeyrthrophyllum ferruginascens, except that the leaves are bright yellow in KOH solution and the costa has a narrow ventral groove (characteristic of Barbula). This species is retained here pending further study; one might hypothesize a chemical treatment used during collecting that might have changed the color reaction, but casual experiments show that neither boiling in formaldehyde solution or in ethyl alcohol causes irreversible changes to the red KOH reaction of true B. ferruginascens.

Additional literature: Abramova et al. (1967), Coats and Mahler (1985), Conard (1945a, 1951a), Crum (1956, 1965d, 1967a), Crundwell (1976), Dhingra-Babbar (1988), Dhingra-Babbar and Chopra (1985), Field (1990), Hoffmann (1957), Maheu (1908), Roorda van Eysinga (1972), Saito (1971a, Sharma and Chopra (1987), Sharma and Sharma (1980, 1986), 1975a), Steere (1938a, 1939b), Takio (1989), Takio et al. (1986), Weber (1972), Zander (1979f, 1981a). Most bibliographic references to Barbula also discuss species of Didymodon sensu Saito (1975a) and the present treatment.

Number of accepted species: 205, plus 8 remaining in Hydrogonium, 1 in Semibarbula, and 3 in Streblotrichum.

Species examined: B. afrofontana (NY), B. agraria, B. arcuata (BM, BUF, FH, NY, TENN), B. amplexifolia (BM, BUF, MICH, NY), B. bicolor (BUF), B. calycina (NY), B. calyculosa (NY), B. clavicostata (PC), B. comosa (NY), B. convoluta, B. costesii (NY), B. crocea (BUF), B. ehrenbergii, B. enderesii (BUF), B. eubryum (BUF, H, US), B. eustegia (NY), B. fendleri (NY), B. fidelis (NY), B. hiroshii (TNS), B. hispaniolensis (NY), B. indica, B. integrifolia (US), B. isoindica (NY), B. javanica (NY), B. lambarenensis (NY), B. leucodontoides (NY), B. microcalycina (NY), B. munyensis(NY), B. occidentalis (NY), B. orizabensis (BM, BUF, FH, TENN), B. pachyloma (BUF), B. peruviana (NY)—near B. indica, B. pseudoehrenbergii (NY), B. rechingeri (H), B. riograndensis (BUF, FH), B. semirosulata (PC), B. spathulifolia (BM), B. subcalycina (NY), B. williamsii (NY), B. unguiculata, B. zambesiaca (NY).

New heterotypic synonymy: Barbula tonkinensis (Besch.) Broth. = Barbula indica (Hook.) Spreng.

New combinations and new names: Barbula clavicostata (Ren. & Hilp.) Zand., comb. nov. (Hyophila clavicostata Ren. & Card., Act. Soc. Linn. Bordeaux 53: 21, 1898 and Prodr. Fl. Bryol. Madag. 123, 1898; Hydrogonium clavicostatum (Ren. & Card.) Hilp.). Barbula isoindica Zand., nom. nov. (Pottia papillinervis Lor., Moostud. 160, 1864; Barbula papillinervis (Lor.) Broth., hom. illeg., Nat. Pfl. 1(3): 408, 1902). Barbula semirosulata Zand., nom. nov. (Gymnostomiella rosulata P. Varde, Rev. Bryol. Lichénol. 26: 1, 1957). Barbula (sect. Hydrogonium) spathulifolia (Dix. & P. Varde) Zand., comb. nov. (Merceyopsis spathulifolia Dix. & P. Varde, Arch. Bot. 1(8–9): 164, 1927).