The Moss Families of the British Isles


L. Watson and M. J. Dallwitz


Gametophyte. Acrocarpous; forming patches (these small and lax). Mature plants 5–10 mm high. Paraphyllia absent. Pseudoparaphyllia absent. Stems not tomentose; with a differentiated central strand. The leaves of main stems and branches similar in form; bilaterally symmetrical; lanceolate, or lingulate; spiral; not crisped when dry (erect-flexuose with incurved tips when dry, patent when moist); not plicate. Leaf bases not sheathing; not decurrent. The leaves single-nerved. The leaf nerves extending to the leaf tip; excurrent. Leaf blade margins flat, or revolute or recurved; unistratose (in L. gaudichaudii); entire, or denticulate to dentate (sometimes, near the tip?). Leaf blades not conspicuously bordered. The basal leaf cells more or less isodiametric; hexagonal to rounded; smooth. The walls of basal leaf cells thick; straight. The angular cells not well differentiated. The mid-leaf cells more or less isodiametric; hexagonal to rounded; smooth. The walls of the mid-leaf cells thick; straight.

Plants dioecious. Plants gemmiferous; the gemmae in leaf axils and or on rhizoids (in the axils, uniseriate).

Sporophyte. Capsules exserted; erect; symmetrical; straight; narrowly sub-cylindric; not waisted; neither flattened nor angular; without an externally conspicuous apophysis; with an annulus; with a peristome (this perfect). The peristome double. The peristome teeth thin, membranous, and transversely barred; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome well developed. The operculum rostrate. Setae long; straight.

Ecology. Confined in Britain to the trunks of the tree fern, Dicksonia antactica. Commonly epiphytic, found in Britain on trunks of the introduced tree fern, Dicksonia antarctica.

Cytology. Haploid chromosome number, n = 10 and 20 (in Tasmania).

British representation. 1 species. Leptotheca. Ireland (only in South Kerry).

Classification. Class Bryopsida; Subclass Bryideae; Order Rhizogoniales.

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.’.