The Moss Families of the British Isles


L. Watson and M. J. Dallwitz




Gametophyte. Pleurocarpous; forming tufts, or forming patches (the primary stems stoloniform, the secondary stems more or less erect and irregularly branched). Paraphyllia present, or absent. The leaves of main stems and branches markedly different in form (those on the primary stems smaller and different in shape). The leaves neither sphagnoid nor leucobryoid. The leaves ovate to narrowly lanceolate (sometimes deltoid), or lingulate; spiral; single-nerved. The leaf nerves extending beyond the middle of the leaf, but not to the tip. Leaf blade apices obtuse, or pointed; apiculate, or not apiculate; apically rounded, or apically acute to acuminate. Leaf blade margins narrowly revolute or recurved, or flat; entire, or denticulate to dentate (or crenulate). Leaf blades not conspicuously bordered. The basal leaf cells somewhat longitudinally elongated to longitudinally much elongated; papillose. The angular cells clearly differentiated to not well differentiated. The mid-leaf cells more or less isodiametric to somewhat longitudinally elongated; hexagonal to rounded; 1- or 2–3 papillose. The walls of the mid-leaf cells thick; straight.

Plants dioecious.

Sporophyte. Capsules exserted; erect; symmetrical; sometimes slightly curved, or straight; sub-cylindric, or ellipsoid to ovoid; without an externally conspicuous apophysis; with an annulus, or without an annulus. Calyptra symmetrical; splitting down one side. Capsules with a peristome. The peristome single, or single to double. The peristome teeth not grouped; not deeply cleft; not perforated; thin, membranous, and transversely barred; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome when present, reduced to rudimentary; shorter than the outer; with a basal membranous ring; with elongated “processes” (these short, and irregular at least in A. viticulosus); without cilia (or with rudiments only). The operculum conical to rostrate. Setae long to short, sometimes scarcely raised above the branches; straight; straw-coloured in A. viticulosus.

Ecology. Occurring in basic habitats (commonly), or neutral pH conditions, or acid conditions (?). On rocks, logs, tree bases or tree trunks, commonly in basic habitats.

Cytology. Haploid chromosome number, n = 11 (in A. longifolius and A. viticulosus).

British representation. 3 species. Anomodon. Northern Scotland, southern Scotland, northern England, English Midlands, East Anglia, Wales, southeast England, central southern England, southwest England, Isle of Wight, and Ireland (A. viticulosus being the most generally distributed, being often common in basic habitats at low altitudes).

Classification. Class Bryopsida; Subclass Bryideae; Order Hypnales.

Illustrations. • Anomodon attenuatus, A. longifolius and A. viticulosus: Dixon. • Anomodon, with Helodium and Thuidium: 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.’.