The Moss Families of the British Isles


L. Watson and M. J. Dallwitz



Gametophyte. Pleurocarpous; forming patches, or growing through other Bryophytes. Primary stems procumbent (with more or less erect branches). Paraphyllia absent. Pseudoparaphyllia absent. The leaves of main stems and branches similar in form; ovate, or ovate to lanceolate (concave); spiral; faintly single-nerved. The leaf nerves not extending beyond the middle of the leaf, or extending beyond the middle of the leaf, but not to the tip. Leaf blade apices obtuse to pointed; not apiculate; apically acute, or acuminate. Leaf blade margins flat; unistratose; entire. Leaf blades bordered (the marginal cells quadrate, like the alar cells). The basal leaf cells longitudinally much elongated; rhomboidal; smooth. The walls of basal leaf cells thin to thick; straight. The angular cells clearly differentiated (these quadrate-rectangular). The mid-leaf cells somewhat longitudinally elongated to longitudinally much elongated (two to three times as long as wide); rounded to rhomboidal; smooth. The walls of the mid-leaf cells thin to thick; straight.

Plants monoecious; autoecious.

Sporophyte. Capsules exserted; minute; erect; symmetrical, or symmetrical to asymmetrical; straight; ellipsoid; not waisted; without an externally conspicuous apophysis; without an annulus. Calyptra symmetrical; splitting down one side. Capsules with a peristome. The peristome double (but reduced). 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 deep yellow; without cilia. The operculum conical. Setae long; straight.

Ecology. In wet places, or mesophytic. In flood zones of streams, rivers and ditches, often silt-encrusted on wood and bark.

British representation. 1 species. Myrinia (Flood-moss). Southern Scotland, northern England, English Midlands, East Anglia, Wales, southeast England, central southern England, southwest England, and Isle of Wight.

Classification. Class Bryopsida; Subclass Bryideae; Order Hypnales.

Illustrations. • Myrinia pulvinata (with Habrodon): Dixon. Habrodon perpusillus Lindb. Myrinia pulvinata Schp.

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.’.