The Moss Families of the British Isles


L. Watson and M. J. Dallwitz


Clay Earth-moss.

In Dixon’s Dicranaceae.

Gametophyte. Acrocarpous (the capsules at first terminal, but becoming lateral by development of innovations); perennial, densely forming tufts, or forming patches. Mature plants 5–20 mm high. The leaves lanceolate to linear, or subulate; spiral; single-nerved. The leaf nerves extending beyond the middle of the leaf, but not to the tip to extending to the leaf tip; not excurrent. Leaf blade apices pointed; apically acute to acuminate; not hyaline. Leaf blade margins flat. The basal leaf cells longitudinally much elongated; rectangular; smooth. The walls of basal leaf cells thin to thick; straight. The angular cells not well differentiated. The mid-leaf cells somewhat longitudinally elongated to longitudinally much elongated; narrowly hexagonal, or rhomboidal; smooth. The walls of the mid-leaf cells thin to thick; straight.

Sporophyte. Capsules immersed; erect; symmetrical; globose (pellucid); neither flattened nor angular; without an externally conspicuous apophysis; smooth. Calyptra very thin, tearing irregularly. Capsules cleistocarpus; without a peristome. Setae short.

Ecology. More or less mesophytic. On bare, often sandy soil in moist fields, on moorland, in wood rides or by rivers.

British representation. 1 species. Archidium. Northern Scotland, southern Scotland, northern England, English Midlands, East Anglia, Wales, southeast England, central southern England, southwest England, Isle of Wight, and Ireland.

Classification. Class Bryopsida; Subclass Dicranideae; Order Archidales.

Illustrations. • Archidium alternifolium: Dixon. Archidium alternifolium. • Archidium alternifolium: 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.’.