Bryophyte flora of Uganda. 5. Hypnaceae (Part 2)

Plants robust to slender, forming loose to dense mats, often coarsely so, light to dark green, yellowish-brown or golden. Primary stems creeping, radiculose beneath, leaves distant, often eroded, stipitate, stipe inconspicuous to rather elongate. Secondary stems arching or subascending, central strand weak; pseudoparaphyllia foliose. Stem leaves¡ distant, mostly broadly ovateto triangular-lanceolate, rarely ovate-oblong, 0.8–2.0 mm long, apex acuminate, rarely acute or rounded, base short to¡long decurrent; margins plane or occasionally erect near apex, at base reflexed, toothed above, rarely entire; costae short and double, occasionally strong, or single, to 1/2 lamina length; median cells linear, appearing smooth or projecting at distal angles; alar cells few, mostly oblong-rectangular to subquadrate, smooth; branch leaves often complanate, commonly shorter or rarely longer than secondary stem leaves, oblong, oblong-ovate to lanceolate, 0.7–1.5 mm long, often coarsely serrate, costae weak or absent, laminal cells usually strongly papillose by projecting distal angles. Autoicous or dioicous. Perichaetial leaves ovateto triangular-long subulate. Seta to 30 mm long, slender, smooth, often twisted. Capsule suberect to subpendulous, ovoid to shortly cylindrical, 1.5–3 mm long, usually constricted below mouth when dry. Operculum conic to short rostrate. Peristome with exostome teeth cross-striate below, distally papillose, endostome basal membrane high, segments keeled and perforate, lightly papillose, cilia 2–3. Spores papillose. Distinguished from Chryso-hypnum which has the leaf cells protruding as papillae at both ends, stems which are procumbent not stipitate, and pseudoparaphyllia lanceolate not foliose. A number of species have been described for Africa but they are in need of taxonomic revision; only one is confirmed for Uganda.