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| The moss families (Bryophyta, Musci) of Britain and Ireland |
~Dicranaceae
Gametophyte. Acrocarpous; cushion-forming, or forming tufts, or forming patches, or the plants scattered. Non-rosette plants. Mature plants 1–120(–150) mm high (but mostly small plants, usually with unbranched stems). Shoots complanate, or not complanate. Stems not tomentose; with a differentiated central strand. The leaves neither sphagnoid nor leucobryoid. The leaves more or less lanceolate (usually, the upper often longer than the lower), or subulate (sometimes comprising mainly nerve); distichous (Distichium), or not distichous; when not distichous, spiral; more or less secund, or not secund; crisped when dry (rarely), or not crisped when dry; single-nerved. The leaf nerves extending beyond the middle of the leaf, but not to the tip to extending to the leaf tip; excurrent to not excurrent (sometimes percurrent); incorporating stereids (these in two bands). Leaf blade apices apically acute, or acuminate; conspicuously hyaline (?), or not hyaline. Leaf blade margins flat, or involute or incurved, or revolute or recurved. Leaf blades not conspicuously bordered. The basal leaf cells somewhat longitudinally elongated to longitudinally much elongated; rectangular to linear; smooth. The walls of basal leaf cells straight. The angular cells not well differentiated. The mid-leaf cells more or less isodiametric to longitudinally much elongated; quadrate to linear; smooth. The walls of the mid-leaf cells thin to thick; straight.
Plants monoecious, or dioecious (most Ditrichum species); when monoecious, autoecious, or paroecious, or synoecious.
Sporophyte. Capsules immersed (Pseudephemerum), or immersed to emergent (e.g., in Pleuridium), or exserted; erect, or inclined; symmetrical, or asymmetrical; straight, or curved; globose, or sub-cylindric, or ellipsoid, or ovoid, or gibbous; with an externally conspicuous apophysis, or without an externally conspicuous apophysis; smooth, or striate and becoming regularly furrowed when dry and empty; with an annulus, or without an annulus. Calyptra symmetrical; splitting down one side, or with two or more splits. Capsules cleistocarpus (Pleuridium, Pseudephemerum), or dehiscing via a lid; with a peristome, or without a peristome (when cleistocarpus). The peristome when present single. The peristome teeth when present, 16; not grouped; deeply cleft (often almost to the base, into 32 divisions), or not deeply cleft; not perforated, or perforated; thin, membranous, and transversely barred; when present, interiorly exhibiting a fine longitudinal dividing line between the transverse bars; terete, filiform and smooth, or smooth below and papillose above. The operculum when present, conical to rostrate, or subulate (the cleistocarpous capsule of Pleuridium with a blunt apiculus, that of Pseudephemerum beaked). Setae short to long; straight, or curved.
Ecology. In diverse habitats.
Cytology. Haploid chromosome number, n = 12, 13, 14, 24, 26, and 28 (rarely with a supernumerary).
Representation in Britain and Ireland. 19 species. Ceratodon (Redshank Mosses), Cheilothela (Rabbit Moss), Distichium (Distichiums), Ditrichum (Ditrichums and Path-moss), Pleuridium (Earth-mosses), Pseudephemerum (Delicate Earth-moss, which seems to fit better here than in Dicranaceae, to which it is commonly referred), Saelania (Dew-moss), Trichodon (Cylindric Ditrichum). Northern Scotland, southern Scotland, northern England, English Midlands, East Anglia, Wales, southeast England, central southern England, southwest England, Isle of Wight, and Ireland.
Classification. Class Bryopsida; Subclass Dicranideae; Order Dicranales.
Comments. The upper leaves usually longer than the lower leaves.
Illustrations. • Distichium, Ditrichum and Pleuridium, with Seligeriaceae. DITRICHACEAE: A, Pleuridium subulatum (Hedw.) Lindb.; B, Trichodon cylindricus (Hedw.) Grout; C, Ditrichum pusillum (Hedw.) Hampe; E, Ditrichum lineare (Sull.) Hampe; F, Ditrichum zonatum (Brid.) Limpr.; G, Ditrichum subulatum Hampe; H, Ditrichum flexicaule (Schimpe) Hampe; I, Distichium capillaceum (Hedw.) Br. Eur.; J, Distichium inclinatum (Hedw.) P. Beauv. SELIGERIACEAE: K, Seligeria donniana (Smith) G. Müll.; S. pusilla (Hedw.) Br. Eur.; S. acutifolia Lindb.
From Dixon and Jameson (1924), the unscaled screen display approximately doubling the magnifications given with their individual figures. 1, leaf or stem leaf where these differ; 2, branch-leaf; 3, perichaetial leaf; 4, perigonial leaf; 5, capsule; 6, peristome; 7, calyptra; 8, spores; 9, inflorescence; 10, gemmae; 11, paraphyllia; 12, stoma of capsule; *, plant, or part of one. Qualifications: a, apex; b, base; c, cells at one third from the apex; cv, ventral aspect of cells; cd, dorsal aspect of cells; bc, basal cells; x, section. • Ceratodon and Saelania (with Rhabdoweisiaceae and Seligeriaceae: Dixon. DITRICHACEAE: F, Saelania glaucescens (Hedw.) Broth.; G, Ceratodon purpureus (Hedw.) Brid. ssp. purpureus; H, Ceratodon purpureus ssp. conicus (Hampe) Dix. RHABDOWEISIACEAE: I, Rhabdoweisia fujax (Hedw.) Br. Eur.; J, Rhabdoweisia crispata (With.) Lindb.; K, Rhabdoweisia crenulata (Mitt.) Jameson; L, Oreoweisia bruntonii (Sm.) Milde; M, Cynodontium poycarpon (Hedw.) Schimp.; N, Cynodontium strumiferum (Hedw.) De Not. SELIGERIACEAE: A, Seligeria trifaria (Brid.) Lindb.; B, Seligeria calycina Mitt. ex Lindb.; C, Seligeria calcarea (Hedw.) Br. Eur.; D, Seligeria recurvata (Hedw.) Br. Eur.; E, Brachydontium trichodes (Web.) Milde.
From Dixon and Jameson (1924), the unscaled screen display approximately doubling the magnifications given with their individual figures. 1, leaf or stem leaf where these differ; 2, branch-leaf; 3, perichaetial leaf; 4, perigonial leaf; 5, capsule; 6, peristome; 7, calyptra; 8, spores; 9, inflorescence; 10, gemmae; 11, paraphyllia; 12, stoma of capsule; *, plant, or part of one. Qualifications: a, apex; b, base; c, cells at one third from the apex; cv, ventral aspect of cells; cd, dorsal aspect of cells; bc, basal cells; x, section. • Pseudephemerum and Pleuridium: Dixon. DITRICHACEAE: F, Pseudephemerum nitidum (Hedw.) Reim. G, Pleuridium acuminatum Lindb.
From Dixon (1924), the unscaled screen display about 3X the magnifications given with his individual figures. 1, leaf or stem leaf where these differ; 2, branch-leaf; 3, perichaetial leaf; 4, perigonial leaf; 5, capsule; 6, peristome; 7, calyptra; 8, spores; 9, inflorescence; 10, gemmae; 11, paraphyllia; 12, stoma of capsule; *, plant, or part of one. Qualifications: a, apex; b, base; c, cells at one third from the apex; cv, ventral aspect of cells; cd, dorsal aspect of cells; bc, basal cells; x, section. Pleuridium acuminatum. Pseudephemerum nitidum. • Distichium capillaceum and Ditrichum heteromallum: Berkeley. DITRICHACEAE: 5, Ditrichum heteromallum (Hedw.) Britton; a, habit; b, leaf; c, capsule; d, part of peristome. 7, Distichium capillaceum (Hedw.) Br. Eur.; a, habit; b, leaf; c, capsule; d, part of peristome; e, part of annulus.
From Berkeley (1863, Plate 22). The approximate 1 cm scale applies to the whole plant (habit) illustrations only. • Ceratodon (with assorted dicranoid taxa): Berkeley. DITRICHACEAE: 5, Ceratodon purpureus (Hedw.) Brid.; a, habit; b, leaf, c, capsule; d, part of peristome; e, detail of peristome tooth tip. DICRANACEAE: 4, Campylopus flexuosus (Hedw.) Brid.; a, habit; b, leaf; c, calyptra; d, capsule. 7, Dicranum scoparium Hedw.; a, habit; b, leaf; c, part of peristome. 8, Dicranella heteromalla (Hedw.) Schimp.; a, habit; b, leaf; c, capsule; d, part of peristome. 10, Arctoa fulvella (Dicks.) R. Br.; a, habit; b, leaf; c, capsule; d, part of peristome. RHABDOWEISIACEAE: 9, Oreoweisia bruntonii (Sm.) Milde; a, habit; b, leaf; c, capsule; d, part of peristome. LEUCOBRYACEAE: 6, Leucobryum glaucum (Hedw.) Ångstr.; a, habit; b, leaf; c, leaf tip; d, capsule; e, part of peristome.
From Berkeley (1863, Plate 23). The approximate 1 cm scale applies to the whole plant (habit) illustrations only.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The moss families (Bryophyta, Musci) of Britain and Ireland. Version: 5th August 2019. delta-intkey.com’.
