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| The moss families (Bryophyta, Musci) of Britain and Ireland |
Rock-mosses.
Gametophyte. Acrocarpous; cushion-forming, or forming tufts (the stems rooting only at their bases, the leaves usually conspicuously hygroscopic). Mature plants 5–80(–100) mm high. The branches in fascicles. The leaves bilaterally symmetrical to markedly asymmetrical (often curved to one side); ovate to narrowly lanceolate, or spathulate to obovate, or linear (then abruptly narrowed above the base to become so); spiral; secund (or curved to one side, often), or not secund; not crisped when dry; nerveless, or single-nerved. The leaf nerves when present extending beyond the middle of the leaf, but not to the tip, or extending to the leaf tip; excurrent (slightly, in A. crassinervia), or not excurrent. Leaf blade apices obtuse to pointed; apiculate, or not apiculate; apically rounded to acuminate. The basal leaf cells somewhat longitudinally elongated, or longitudinally much elongated; papillose, or smooth. The walls of basal leaf cells thick; straight, or sinuous. The angular cells not well differentiated. The mid-leaf cells more or less isodiametric to somewhat longitudinally elongated; quadrate to rectangular, or rounded; papillose, or smooth. The walls of the mid-leaf cells thick; sinuous.
Plants monoecious, or dioecious (A. nivalis only); when monoecious, autoecious.
Sporophyte. Capsules exserted (the mature capsule becoming exserted via a “pseudopodium”, which develops by elongation of the basal part of the sporogonium); erect; symmetrical; ellipsoid to ovoid, or pyriform; with an externally conspicuous apophysis. Calyptra small; symmetrical; with two or more splits. Capsules dehiscing via longitudinal slits (i.e., the lid persisting, instead of being shed in the usual fashion); without a peristome. Setae absent.
Ecology. Occurring in basic habitats, neutral pH conditions, and acid conditions. Growing on basic and acidic rocks, mostly at high altitudes or montane.
Cytology. Haploid chromosome number, n = 9 (+ m), or 10, or 11 (for the three species recorded).
Representation in Britain and Ireland. 11 species. Andreaea. Northern Scotland, southern Scotland, northern England, English Midlands, Wales, southeast England, and Ireland.
Classification. Class Andraeopsida; Order Andreaeales.
Comments. Plants very fragile, reddish purple or brown to blackish.
Illustrations. • Andreaea: Dixon. ANDREAEACEAE: A, Andreaea rupestris Hedw. B, A. alpina Hedw. C, A. rothii Web. & Mohr. D, A. crassinervia Bruch.
From Dixon (1924), the unscaled screen display approximately doubling the magnifications given with his 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. • Andreaea and Sphagnum: Berkeley. ANDREAEACEAE: 6, Andreaea alpina Hedw.: a, habit; b, leaves; c, leaf detail; d, young capsule; e, dehisced capsule. 7, A. rothii Web. & Mohr: a, habit; b, leaves; c, capsule. SPHAGNACEAE: 1, Sphagnum palustre L.: a, habit; b, stem cells; c, branch leaf; d, capsule. 2, S. compactum DC.: a, habit; b, stem cells; c, branch leaf; d, capsule. 3, S. tenellum (Brid.) Brid.: a, habit; b, stem cells; c, branch leaf. 4, S. subnitens Russ. & Warnst.: a, habit; b, branch leaf; c, capsule, with remains of calyptra; d, detached lid of capsule. 5, S. squarrosum Crome: a, habit; b, branch leaf; c, capsule with remains of calyptra.
From Berkeley (1863). The approximate 1 cm scale added at upper left 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’.
