The Moss Families of the British Isles


L. Watson and M. J. Dallwitz


Excluding Aulacomniaceae.

Gametophyte. Acrocarpous; forming tufts. Primary stems erect. Mature plants 10–150 mm high. Plants exhibiting comal tufts of leaves, or without comal tufts. The leaves oblong, or ovate, or narrowly lanceolate to linear, or lingulate; spiral (or detectably 5-ranked, in Paludella). Leaf bases decurrent (e.g., in Paludella), or not decurrent. The leaves single-nerved. The leaf nerves extending beyond the middle of the leaf, but not to the tip. Leaf blade apices obtuse, or pointed; apically rounded, or apically acute, or acuminate. Leaf blade margins proximally involute or incurved to revolute or recurved, or flat; distally dentate. Leaf blades not conspicuously bordered. The basal leaf cells longitudinally much elongated; rectangular; papillose (or mamillose), or smooth. The walls of basal leaf cells thin to thick; straight. The angular cells not well differentiated. The mid-leaf cells more or less isodiametric, or somewhat longitudinally elongated; rectangular, or hexagonal, or rounded; papillose (or mammilose), or smooth. The walls of the mid-leaf cells thin to thick; straight.

Sporophyte. Capsules exserted; more or less inclined; asymmetrical; more or less curved (only slightly so, from an erect neck, in Paludella); clavate, or pyriform, or ellipsoid (Paludella); with an externally conspicuous apophysis. Calyptra asymmetric. Capsules with a peristome. The peristome double. The peristome teeth 16; not deeply cleft; not perforated; thin, membranous, and transversely barred; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome well developed, or reduced; about equalling the outer (Paludella), or exceeding the outer; with elongated “processes”. The processes of the inner peristome 16; alternating with the teeth of the outer peristome. The inner peristome ciliate, or without cilia. The operculum convex. Setae long and slender; straight.

Ecology. In wet places; occurring in basic habitats. In fens, dune slacks, basic montane flushes and rock crevices.

Cytology. Haploid chromosome number, n = 10, 13, 14, 18, and 20.

British representation. 5 species. Amblyodon (Short-tooth Hump-moss), Leptobryum (Golden Thread-moss), Meesia (Hunp-mosses), Paludella (Tufted Fen-moss). 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 Bryideae; Order Splachnales.

Illustrations. • Amblyodon, Meesia, Paludella: Dixon. • Leptobryum pyriforme: Dixon. Leptobryum pyriforme. • Meesia trichoides: Berkeley. • Amblyodon, with Cinclidium and Plagiomnium (Mniaceae): Berkeley. • Leptobryum, with Bryaceae and Orthodontium: 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.’.