The Moss Families of the British Isles


L. Watson and M. J. Dallwitz




Gametophyte. Pleurocarpous (with rather regularly pinnate branching); forming tufts, or mat or turf forming, or forming patches. Non-rosette plants. Primary stems erect to procumbent. Shoots not complanate. Paraphyllia (falcato-) present, or absent. Pseudoparaphyllia absent (never mentioned). Stems tomentose below (often matted with rhizoids), or not tomentose. The leaves of main stems and branches similar in form to markedly different in form (the stem leaves larger and broader); bilaterally symmetrical; ovate (or deltoid), or lanceolate to narrowly lanceolate; spiral; secund (or falcato-secund). Leaf bases not sheathing (but cordate); decurrent. The leaves single-nerved. The leaf nerves extending beyond the middle of the leaf, but not to the tip, or extending beyond the middle of the leaf, but not to the tip to extending to the leaf tip (reaching at least to the base of the acumen); not excurrent. Leaf blade apices pointed; acuminate. Leaf blade margins flat; unistratose; entire, or denticulate. Leaf blades not conspicuously bordered. The basal leaf cells somewhat longitudinally elongated, or longitudinally much elongated (?); irregularly rectangular; smooth. The walls of basal leaf cells thick; straight. The angular cells clearly differentiated (enlarged, forming distinct auricles which are decurrent almost to the nerve). The mid-leaf cells longitudinally much elongated; rhomboidal to vermicular; papillose, or smooth. The walls of the mid-leaf cells thin; straight.

Plants dioecious.

Sporophyte. Capsules exserted; inclined, or horizontal; at least somewhat somewhat asymmetrical (gibbous), or symmetrical; more or less curved; sub-cylindric to ellipsoid; distinctly waisted to not waisted; neither flattened nor angular; without an externally conspicuous apophysis; smooth; with an annulus. Calyptra glabrous; symmetrical; splitting down one side. Capsules with a peristome. The peristome double. The peristome teeth 16; not grouped; 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; shorter than the outer to exceeding the outer (?); with a basal membranous ring; with elongated “processes” (these broad). The processes of the inner peristome 16; alternating with the teeth of the outer peristome. The inner peristome ciliate (the cilia entire). The operculum shortly conical to mamillate. Setae long; reddish; smooth.

Ecology. In wet places, or mesophytic; occurring in mostly basic habitats.

British representation. 2 species. Cratoneuron. 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 Hypnales.

Illustrations. • Cratoneuron (with Amblystegium, Campylium and Drepanocladus): Dixon. • Cratoneuron (with Campyliaceae, Palustriella and Rhytidiadelphus): 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.’.