The Moss Families of the British Isles


L. Watson and M. J. Dallwitz


Cf. Hylocomiaceae, Leskeaceae.

Gametophyte. Pleurocarpous; forming patches (these coarse, lax). Primary stems erect to procumbent (forked, irregularly pinnate). Paraphyllia absent. Pseudoparaphyllia present (lanceolate-subulate). The leaves of main stems and branches similar in form (the stem leaves larger); bilaterally symmetrical; ovate to narrowly lanceolate (or deltoid); spiral; (falcato-) secund. Leaf bases not decurrent. The leaves single-nerved (but the nerves apically forked). The leaf nerves not extending beyond the middle of the leaf to extending beyond the middle of the leaf, but not to the tip. Leaf blade apices pointed; not apiculate; acuminate. Leaf blade margins revolute or recurved (from near the base to the apex); unistratose; denticulate (above). Leaf blades not conspicuously bordered. The basal leaf cells somewhat longitudinally elongated to longitudinally much elongated; rhomboidal; smooth. The walls of basal leaf cells straight. The angular cells clearly differentiated. The mid-leaf cells longitudinally much elongated; linear, or vermicular; papillose. The walls of the mid-leaf cells thick; straight.

Plants dioecious. Parapyhyses present among the reproductive organs, or absent.

Sporophyte. Capsules exserted; horizontal; asymmetrical; curved; shortly sub-cylindric; neither flattened nor angular; without an externally conspicuous apophysis; smooth. Calyptra large and covering the well-developed capsule; splitting down one side (?). Capsules with a peristome. The peristome double. The peristome teeth 16; not grouped; not deeply cleft (?); thin, membranous, and transversely barred; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome well developed; with a basal membranous ring (this high); with elongated “processes”. The processes of the inner peristome 16. The inner peristome ciliate (with 1–3 cilia). The operculum obliquely rostellate. Setae long.

Ecology. In wet places, or mesophytic, or xerophytic; occurring in basic habitats. In basic grassland, rarely in dune grassland.

Cytology. Haploid chromosome number, n = 10.

British representation. 1 species. Rhytidium (Wrinkle-leaved Feather-moss). Northern Scotland, southern Scotland, northern England, English Midlands, East Anglia, Wales, and Ireland.

Classification. Class Bryopsida; Subclass Bryideae; Order Hypnales.

Illustrations. • Rhytidium (with Hylocomiaceae): 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.’.