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ERPODIACEAE

(N.G. Hodgetts)

Since the recent revision of the family (Stone 1997), the Erpodiaceae contain the single genus Erpodium and some 35 species of mostly tropical and south temperate distribution. The family is placed in the Orthotrichales.

Erpodium (Brid.) Müll.Hal.

Twelve species in sub-Saharan Africa; about 35 species widely distributed in tropical and subtropical regions.

Plants small to medium-sized, in loose to dense mats, dull light to dark green. Stems creeping, to 10 mm long, irregularly pinnately branched, terminal stems and branches often spreading to ascending and curled, radiculose beneath. Leaves appressed to weakly complanate, occasionally appearing 4-ranked, ovate, ovate-oblong to nearly orbicular, 0.5-1.2 mm long, symmetric to asymmetric, concave, apex acuminate to acute or rounded, apiculate or piliferous; margins plane, entire; laminal cells smooth or pluripapillose, apical cells elongate or isodiametric; median cells quadrate- to hexagonal-rounded and horizontally arranged or oblate; alar region differentiated, cells oblong, oblately arranged. Perichaetial leaves often enveloping sporophyte, oval to oblong. Seta short, 0.2-0.8 mm long. Capsule immersed to shortly exserted, erect to subinclined, urn short-cylindrical, 0.8-1.5 mm long; stomata absent or several at base of urn, superficial; annulus absent or compound and persistent. Operculum conic-rostrate. Peristome absent or poorly developed, papillose. Calyptra mitrate-short campanulate or elongate and twisted, plicate and lobed at base, or appearing cucullate, roughened or not. Spores smooth to lightly papillose.

Habitat. Usually epiphytic, on tree trunks and exposed roots or logs, in shaded or partially exposed sites; semi-arid forests and isolated trees (e.g. on roadsides, in gardens), from near sea level to 1700 m.

Discussion. The genus is characterised by its usually epiphytic habitat, opaque leaves and the smooth or pluripapillose laminal cells. The plants are often closely appressed to the substrate, sometimes (non-piliferous species) superficially resembling a liverwort such as Frullania. Crum (1972) provided an account of the family as a whole. Further information for the family in Africa, including keys, was provided by Egunyomi (1980), Hodgetts (1997) and Magill & van Rooy (1998).

Literature. Crum, H. 1972. A taxonomic account of the Erpodiaceae. Nova Hedwigia 23: 201-224. Egunyomi, A. 1980. Mosses from Nigeria III: new records from the Middle-Belt area. Journal of the Hattori Botanical Laboratory 48: 187-193. Hodgetts, N.G. 1997. British Bryological Society expedition to Mulanje Mountain, Malawi 3. Erpodiaceae (Musci). Journal of Bryology 19: 113-118. Magill, R.E. & van Rooy, J. 1998. - see general ref. Stone, I.G. 1997. A revision of Erpodiaceae with particular reference to Australian taxa. Journal of Bryology 19: 485-502.


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accepted 17.04.2000