The Moss Families of the British Isles


L. Watson and M. J. Dallwitz



Gametophyte. Pleurocarpous; forming patches, or the plants scattered (the stems and branches procumbent to ascending). Primary stems yellow or red. Shoots complanate, or not complanate. The leaves of main stems and branches similar in form (the branch leaves sometimes narrower); oblong to ovate, or ovate to narrowly lanceolate; spiral; nerveless, or double-nerved. The leaf nerves when present, not extending beyond the middle of the leaf. Leaf blade apices obtuse, or pointed; bluntly apiculate (sometimes, in Entodon), or not apiculate; apically rounded to apically acute, or acuminate (in Orthothecium). Leaf blade margins distally involute or incurved, or flat; entire. Leaf blades not conspicuously bordered. The basal leaf cells longitudinally much elongated; narrowly rhomboidal to vermicular; smooth. The walls of basal leaf cells thin to thick, or thick; straight. The angular cells clearly differentiated to not well differentiated (these quadrate, in Entodon), or not well differentiated. The mid-leaf cells longitudinally much elongated. The marginal mid-leaf cells more than twice as long as wide (supposedly distinguishing this family from Leucodontaceae). The mid-leaf cells narrowly rhomboidal to vermicular; smooth. The walls of the mid-leaf cells thin to thick, or thick; straight.

Plants monoecious, or dioecious; when monoecious, autoecious. Parapyhyses present among the reproductive organs, or absent.

Sporophyte. Capsules exserted; erect, or erect to inclined; slightly asymmetrical to symmetrical; straight to curved; sub-cylindric, or ellipsoid to ovoid; without an externally conspicuous apophysis; smooth; with an annulus, or without an annulus. Calyptra glabrous; symmetrical; splitting down one side. Capsules with a peristome. The peristome double. The peristome teeth not grouped; not deeply cleft (?); perforated; thin, membranous, and transversely barred; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome well developed, or reduced; shorter than the outer to about equalling the outer (equal to almost as long, in Entodon); with a basal membranous ring (but this short, in Orthothecium), or without a basal membranous ring (Entodon); with elongated “processes”. The processes of the inner peristome alternating with the teeth of the outer peristome. The inner peristome ciliate, or without cilia. The cilia and processes of the endostome not united into a conical lattice. The operculum rostellate to rostrate. Setae long; curved (?); smooth.

Ecology. In wet places, or mesophytic; occurring in basic habitats. Orthothecium on (usually vertical) rock faces, Entodon on well drained basic soil, in turf, among rocks or scree, occasionally in chalk or limestone grassland.

British representation. 1 species, or 3 species (if Orthothecium is included). Entodon (Cylinder-moss) and Orthothecium (the latter perhaps better referred to Hypnaceae). 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 Bryideae; Order Hypnales.

Illustrations. • Entodon and Orthothecium: Dixon. Orthothecium intricatum. Orthothecium rufescens. Entodon concinnus. • Orthothecium, with Brachytheciaceae, Ptychodium and Tomentypnum: Dixon.

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.’.