The Moss Families of the British Isles


L. Watson and M. J. Dallwitz



Excluding Diphysciaceae.

Gametophyte. Minute, stemless plants, arising from brownish protonemal mats, leafless apart from green, fringed perichaetial bracts. Acrocarpous; the tiny plants solitary, or the plants scattered (arising from brownish protonemal mats). Mature plants to about 0.5–2 mm high (minute). Leaves absent (i.e., having only the minute, ciliate perichaetial bracts).

Plants dioecious.

Sporophyte. Capsules exserted (with a stout, rough seta about 10–15 mm long); inclined; asymmetrical; slightly curved, or straight; obliquely ovoid (egg-shaped); with an externally conspicuous apophysis, or without an externally conspicuous apophysis. Calyptra very small; symmetrical. Capsules with a peristome. The peristome double (the outer peristome comprising 1 or 4 rows of filiform or linear teeth). The peristome teeth not grouped; not deeply cleft; not perforated; solid, without transverse bars (derived from several concentric series of sporogonium cells). The inner peristome well developed (comprising a pale, tubular, 32-plicate membrane); without “processes”; without cilia. The operculum narrowly conical. Setae short or long; straight.

Ecology. Mesophytic; occurring in neutral pH conditions to acid conditions. On humus-rich acidic or sandy soil, or on rotting wood, especially with conifers.

Cytology. Haploid chromosome number, n = 8.

British representation. 2 species. Buxbaumia. Southern Scotland, northern England, English Midlands, East Anglia, Wales, southeast England, central southern England, southwest England, Isle of Wight, and Ireland (B. aphylla being rare but of widespread occurrence, with B. viridis only in Scotland and very rare).

Classification. Class Polytrichopsida; Order Tetraphidales.

Comments. Buxbaumia aphylla is a strange genus, without chlorophyll (presumably saprophytic?), and B. aphylla was at one time considered to be a fungus!.

Illustrations. • Buxbaumia, with Diphyscium: Dixon. Buxbaumia aphylla. Buxbaumia viridis. Diphyscium foliosum. • Buxbaumia aphylla, with Diphyscium foliosum: 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.’.