The Moss Families of the British Isles


L. Watson and M. J. Dallwitz



In Dixon’s Hypnaceae.

Gametophyte. Pleurocarpous; usually more or less conspicuously dendroid; cushion-forming. Primary stems procumbent (creeping, with scale leaves only, the secondary stems erect and much-branched towards their tops). Mature plants 20–100 mm high. Stems with a differentiated central strand. The leaves of main stems and branches markedly different in form (the primary and secondary stem leaves scale-like); on the branches, ovate to narrowly lanceolate, or lingulate (plicate); spiral (?); secund, or not secund; longitudinally plicate; nerveless (stem leaves), or single-nerved (branch leaves). The leaf nerves of branch leaves, extending beyond the middle of the leaf, but not to the tip. Leaf blade margins coarsely dentate (distally). The basal leaf cells longitudinally much elongated; rhomboidal to linear; smooth. The walls of basal leaf cells thin; straight. The angular cells not well differentiated. The mid-leaf cells longitudinally much elongated; narrowly hexagonal, or rhomboidal; smooth. The walls of the mid-leaf cells thin; straight.

Plants dioecious.

Sporophyte. Capsules exserted; erect; symmetrical to asymmetrical; straight to curved; slightly gibbous, or sub-cylindric; without an externally conspicuous apophysis; without an annulus. Calyptra splitting down one side. Capsules with a peristome. The peristome double. The peristome teeth reddish, 16; not grouped (basally confluent); not deeply cleft; papillose; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome well developed; exceeding the outer; with elongated “processes”. The processes of the inner peristome 16 (these yellow and scalariform); alternating with the teeth of the outer peristome. The inner peristome ciliate to without cilia (the cilia rudimentary). The operculum narrowly conical. Setae long, twisted; flexuose.

Ecology. In wet places to mesophytic. In damp, marshy places, wet grassland and dune slacks.

Cytology. Haploid chromosome number, n = 11.

British representation. 1 species. Climacium. 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. • Climacium dendroides. Climacium dendroides. • Climacium dendroides: 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.’.