The Moss Families of the British Isles


L. Watson and M. J. Dallwitz



Gametophyte. Acrocarpous (always?); forming tufts, or forming patches, or the plants scattered. Mature plants 1–100 mm high. Plants exhibiting comal tufts of leaves, or without comal tufts. Shoots complanate, or not complanate. Stems not tomentose. The leaves neither sphagnoid nor leucobryoid. The leaves not distichous; spiral; 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); without stereids. Leaf blade apices not hyaline. The basal leaf cells somewhat longitudinally elongated to longitudinally much elongated; rectangular to linear; smooth. The angular cells not well differentiated. The mid-leaf cells more or less isodiametric to longitudinally much elongated; quadrate to linear; smooth.

Plants monoecious, or dioecious (commonly); when monoecious, autoecious, or paroecious.

Sporophyte. Capsules immersed to emergent (in Blindia caespiticia only), or exserted (the rest); erect, or inclined; symmetrical, or asymmetrical; straight, or curved; when asymmetric, often gibbous, or ovoid, or pyriform, or sub-cylindric; with an externally conspicuous apophysis (occasionally), or without an externally conspicuous apophysis (mostly). The apophysis remaining smooth. Capsules smooth, or striate and becoming regularly furrowed when dry and empty (Brachydontium trichodes, as illustrated by Smith); with an annulus, or without an annulus; dehiscing via a lid; with a peristome, or without a peristome (e.g., Blindia caespiticia). The peristome when present, i.e. usually, single. The peristome teeth when present, 8, or 16; not grouped; deeply cleft (often almost to the base, into 32 divisions), or not deeply cleft (e.g., Seligeria); thin, membranous, and transversely barred; when present and not completely cleft, interiorly exhibiting a fine longitudinal dividing line between the transverse bars. The operculum rostellate to subulate. Setae short to long; curved, or straight.

Ecology. Saxicolous. Saxicolous.

Cytology. Haploid chromosome number, n = 11, 12, 13, and 14 (Blindia not recorded).

British representation. 16 species. Blindia, Brachydontium (Bristle-leaf), Seligeria (Rock-bristle Mosses; including Trochobryum). 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 Seligeriales.

Illustrations. • Seligeria, with Ditrichaceae. • Brachydontium and Seligeria spp. (with Ditrichaceae and Rhabdoweisiaceae): Dixon. • Blindia, with Dicranaceae and Rhabdoweisiaceae: Dixon. • Blindia Brachydontium and Seligeria (with Rhabdoweisia and Weissia): Berkeley.

To view the illustrations with detailed captions, go to the interactive key. This also offers 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.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The moss families of the British Isles. Version: 21st June 2009.’.