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| The moss families (Bryophyta, Musci) of Britain and Ireland |
Shield-mosses.
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.
Representation in Britain and Ireland. 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. BUXBAUMIACEAE: B, Buxbaumia aphylla Hedw.; C, Buxbaumia viridis (Moug. ex DC) Brid. ex Moug. & Nestle. DIPHYSCIACEAE: D, Diphyscium foliosum (Hedw.) Mohr.
From Dixon and Jameson (1924), the unscaled screen display approximately doubling the magnifications given with their individual figures. 1, leaf or stem leaf where these differ; 2, branch-leaf; 3, perichaetial leaf; 4, perigonial leaf; 5, capsule; 6, peristome; 7, calyptra; 8, spores; 9, inflorescence; 10, gemmae; 11, paraphyllia; 12, stoma of capsule; *, plant, or part of one. Qualifications: a, apex; b, base; c, cells at one third from the apex; cv, ventral aspect of cells; cd, dorsal aspect of cells; bc, basal cells; x, section. Buxbaumia aphylla. Buxbaumia viridis. Diphyscium foliosum. • Buxbaumia aphylla, with Diphyscium foliosum: Berkeley. DIPHYSCIACEAE: 5, Diphyscium foliosum (Hedw.) Mohr; a, habit; b, plant, more enlarged; c, capsule; d, calyptra; e, peristome; f, leaf (green) and two perichaetial bracts (brown). BUXBAUMIACEAE: 6, Buxbaumia aphylla Hedw.; a, habit (the plants leafless); b, sporangium; c, calyptra; d, peristome; e, a process from the inner peristome.
From Berkeley (1863, Plate 19). The approximate 1 cm scale applies to the whole plant (habit) illustrations only.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The moss families (Bryophyta, Musci) of Britain and Ireland. Version: 5th August 2019. delta-intkey.com’.
