The Moss Families of the British Isles


L. Watson and M. J. Dallwitz


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.

British representation. 1 species. Catoscopium. Northern Scotland, southern Scotland, northern England, Wales, and Ireland.

Classification. Class Bryopsida; Subclass Bryideae; Order Splachnales.

Illustrations. • Catascopium nigritum: Dixon. Catascopium nigritum. • Catoscopiaceae and Disceliaceae: 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.’.