|
| The moss families (Bryophyta, Musci) of Britain and Ireland |
Down-looking Mosses.
In Dixon’s Bartramiaceae
Gametophyte. Acrocarpous; densely forming tufts (the tufts bright to dark green, blackish below). Mature plants (20–)40–70 mm high. Stems not tomentose. The leaves lanceolate; spiral; single-nerved. The leaf nerves extending to the leaf tip; not excurrent. Leaf blade apices pointed; acuminate. Leaf blade margins revolute or recurved (proximally); entire. The basal leaf cells longitudinally much elongated; rectangular; smooth. The walls of basal leaf cells somewhat thick; straight. The angular cells not well differentiated. The mid-leaf cells more or less isodiametric to somewhat longitudinally elongated; quadrate to rectangular, or rounded; smooth. The walls of the mid-leaf cells somewhat thick; straight.
Plants dioecious.
Sporophyte. Capsules exserted; inclined (cernuous); more or less symmetrical; globose (black and glossy); without an externally conspicuous apophysis; smooth; with a peristome. The peristome single, or single to double (the outer poorly developed, the inner vestigial or lacking). The peristome teeth 16; not grouped; not deeply cleft; not perforated; thin, membranous, and transversely barred. The inner peristome if detectable, without “processes”. The operculum convex. Setae long, to 1 cm, very slender and rigid; straight.
Ecology. Occurring in basic habitats. In montane flushes and dune slacks.
Cytology. Haploid chromosome number, n = 13 and 14.
Representation in Britain and Ireland. 1 species. Catoscopium. Northern Scotland, southern Scotland, northern England, Wales, and Ireland.
Classification. Class Bryopsida; Subclass Bryideae; Order Splachnales.
Illustrations. • Catascopium nigritum: Dixon. CATASCOPIACEAE: Catascopium nigritum (Hedw.) Brid.
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. Catascopium nigritum. • Catoscopiaceae and Disceliaceae: Berkeley. CATOSCOPIACEAE: 7, Catoscopium nigritum (Hedw.) Brid.; a, habit; b, leaves; c, capsule; d, part of peristome. DISCELIACEAE: 6, Discelium nudum (Dicks.) Brid.; a, habit; b, leaf; c, capsule; d, part of peristome, with annulus and spores.
From Berkeley (1863, Plate 15). 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’.
