A New Species of Trichomanes from Eastern Africa

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Like many groups of tropical ferns, the family Hymenophyllaceae is not well represented in continental Africa, where only 30-35 species occur. Despite the moderate number, there is still some disagreement about the specific limits of several species (cf. Schelpe, 1970; Faden, 1974). There has not been a continentwide study of the family since the generic monograph of Copeland (1938), which is incomplete in species coverage and lacks species descriptions. No new species has been described from mainland Africa since Alston (1956). While I was working at the East African Herbarium from 1969 to 1972, I made several collections of a Trichomanes which appeared to represent an undescribed species. Herbarium studies at the Royal Botanic Gardens, Kew and British Museum (Natural History) confirmed this conclusion and revealed that the species is widespread in eastern Africa. Field investigations also showed that it is ecologically distinct from its relatives in East Africa. Trichomanes ramitrichum Faden, sp. nov. Figs. 1-5 Trichomanes sp. A. of Faden in Agnew, Upland Kenya Wild Fls. 29. 1974. Trichomanes borbonicum v. d. Bosch sensu Schelpe in Exell & Launert, Fl. Zambesiaca 76. 1970, pro parte. Trichomanes pyxidiferum L. var. melanotrichum (Schlechtend.) Schelpe sensu Schelpe, op. cit. 78, pro parte. Rhizoma filiforme modice dense vestitum trichomatibus brunneis aliquibusque monopodialiter ramosis. Frondes plerumque bivel tripinnatifidae, in ambitu ovatae ad lineares, 2-14 cm longae, 0.8-3 cm latae, in siccitate plicis, venis falsis carentes. Indusium tubulare, 2-2.5 mm longum, apice bilabiatum, labiis plerumque haud expansis. TYPE: KENYA, Kericho District, South West Mau Forest, along the Kiptiget (Chepkoisi) River, ca. 16 km SSE of Kericho, 0?31'-0?31'30S, 35018'-35019'30E, 1980-2020 m, 12 June 1972, Faden & Grumbley 72/338 (EA; isotypes B, BM, BOL, BR, DSM, GH, K, LISC, LMU, MHU, MO, P, PRE, SRGH, US, WAG, Herb. Pichi-Sermolli). Rhizome filiform, moderately densely and usually persistently covered with dark brown trichomes, at least some trichomes monopodially branched; fronds remote, flabellately divided or, more commonly, 2-3-pinnatifid, ovate to linear in outline, 2-14 cm long, 0.8-3 cm wide; stipe 0.2-2.5 cm long, dark green, blackish at the base, winged in the upper part, with scattered, minute, clavate hairs on both surfaces and occasionally some longer hairs at the base; lamina glabrous except for sparse minute clavate hairs on the veins of both surfaces, false veins wanting, longitudinal drying folds present, pinnule lobes linear; indusia terminal on the basal acroscopic pinnule lobes and sometimes also on the terminal lobes of the pinnae and subterminal basiscopic pinnule lobes, tubular, 2-2.5 mm long, winged for 2/3-3/4 of their length, bilabiate above this, labia rounded to truncate at the apex, usually not spreading, entire or rarely denticulate at the apex, receptacle usually long-exserted. DISTRIBUTION: Uganda, Kenya, Tanzania, Zambia, Rhodesia, and Mozambique.