45. Hydrobryum Endlicher
Hydrobryum Endlicher, Gen. Pl. 1375 (1841), M. Kato, Acta Phytotax. Geobot. 55: 133--165 (2004), rev.
Polypleurella Engler (1927), pro parte.
Euhydrobryum Koidzumi (1931).
Hydroanzia Koidzumi (1935).
Synstylis C. Cusset (1992).
Roots crustose, irregularly lobed, 1--10 (--30) cm in diameter; stems scattered on upper surface of root; vegetative shoots very short, rosette-like; flowering stems simple, very short. Leaves of vegetative stems 2--8, tufted, in 2 rows, linear, up to 12 mm long; leaves of flowering stems imbricate, scale-like, 2--8, in 2 rows, overlapping, enlarged at base, tips linear and caducous or lacking. Spathellas boat-shaped, opening irregularly at tip or splitting down one side, thin, smooth. Flowers solitary, terminal, subsessile, remaining within the leaves; tepals 2 (rarely 1, 3 or 4), linear, 1--1.5 mm long; stamens 1 or 2 (3), borne on andropodium at least as long as filaments; pollen in dyads. Capsules shortly pedicelled, ± ellipsoidal, sometimes laterally flattened; valves equal, each with 5 or 6 (--9) ribs; styles short or 0; stigmas linear to cuneate, entire, toothed or lobed. Seeds 8--60, elliptic-patelliform, surface granular. About twelve spp., NE India, Nepal, Bhutan, S Central China, N Vietnam, Thailand & S Japan, ten ssp. in Thailand. The genus Synstylis was based on Polypleurella micranthera Engler; we are convinced it belongs in the genus Hydrobryum. Diplobryum is also very close to Hydrobryum.