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| The moss families (Bryophyta, Musci) of Britain and Ireland |
Cf. Hylocomiaceae, Leskeaceae
Gametophyte. Pleurocarpous; forming patches (these coarse, lax). Primary stems erect to procumbent (forked, irregularly pinnate). Paraphyllia absent. Pseudoparaphyllia present (lanceolate-subulate). The leaves of main stems and branches similar in form (the stem leaves larger); bilaterally symmetrical; ovate to narrowly lanceolate (or deltoid); spiral; (falcato-) secund. Leaf bases not decurrent. The leaves single-nerved (but the nerves apically forked). The leaf nerves not extending beyond the middle of the leaf to extending beyond the middle of the leaf, but not to the tip. Leaf blade apices pointed; not apiculate; acuminate. Leaf blade margins revolute or recurved (from near the base to the apex); unistratose; denticulate (above). Leaf blades not conspicuously bordered. The basal leaf cells somewhat longitudinally elongated to longitudinally much elongated; rhomboidal; smooth. The walls of basal leaf cells straight. The angular cells clearly differentiated. The mid-leaf cells longitudinally much elongated; linear, or vermicular; papillose. The walls of the mid-leaf cells thick; straight.
Plants dioecious. Parapyhyses present among the reproductive organs, or absent.
Sporophyte. Capsules exserted; horizontal; asymmetrical; curved; shortly sub-cylindric; neither flattened nor angular; without an externally conspicuous apophysis; smooth. Calyptra large and covering the well-developed capsule; splitting down one side (?). Capsules with a peristome. The peristome double. The peristome teeth 16; not grouped; not deeply cleft (?); thin, membranous, and transversely barred; exteriorly with a fine longitudinal dividing line between the transverse bars. The inner peristome well developed; with a basal membranous ring (this high); with elongated “processes”. The processes of the inner peristome 16. The inner peristome ciliate (with 1–3 cilia). The operculum obliquely rostellate. Setae long.
Ecology. In wet places, or mesophytic, or xerophytic; occurring in basic habitats. In basic grassland, rarely in dune grassland.
Cytology. Haploid chromosome number, n = 10.
Representation in Britain and Ireland. 1 species. Rhytidium (Wrinkle-leaved Feather-moss). Northern Scotland, southern Scotland, northern England, English Midlands, East Anglia, Wales, and Ireland.
Classification. Class Bryopsida; Subclass Bryideae; Order Hypnales.
Illustrations. • Rhytidium (with Hylocomiaceae): Dixon. RHYTIDIACEAE: I, Rhytidium rugosum (Hedw.) Kindb. HYLOCOMIACEAE: A, Pleurozium schreberi (Brid.) Mitt.; B, Hylocomium splendens (Hedw.) Br.Eur.; C, Hylocomiastrum umbratum (Hedw.) M. Fleisch.; D, Hylocomiastrum pyrenaicum (Spruce) M. Fleisch.; E, Loeskobryum brevirostre (Brid.) M. Fleisch.; F, Rhytidiadelphus loreus (Hedw.) Warnst.; G, Rhytidiadelphus squarrosus (Hedw.) Warnst.; H, Rhytidiadelphus triquetrus (Hedw.) Warnst.
From Dixon and Jameson (1924), the unscaled screen display approximately doubling the magnifications given with their individual figures. 1, leaf or stem leaf where these differ; 2, branch-leaf; 3, perichaetial leaf; 4, perigonial leaf; 5, capsule; 6, peristome; 7, calyptra; 8, spores; 9, inflorescence; 10, gemmae; 11, paraphyllia; 12, stoma of capsule; *, plant, or part of one. Qualifications: a, apex; b, base; c, cells at one third from the apex; cv, ventral aspect of cells; cd, dorsal aspect of cells; bc, basal cells; x, section.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The moss families (Bryophyta, Musci) of Britain and Ireland. Version: 5th August 2019. delta-intkey.com’.
