13. Hyocomium Bruch & Schimp. in B.S.G. 水梳藓属 shui shu xian shu
Bryol. Eur. 5: 235 (fasc. 55–56 Mon. 1). 1852. Hylocomium subgen. Hyocomium (Bruch & Schimp.) Kindb., Eur. N. Amer. Bryin. 1: 39. 1897.
Plants soft, elongate, yellowish green or bright green, somewhat glossy, in lax mats. Stems prostrate, numerous rhizoids here and there, pinnately to bipinnately branched, in distinct layers; branches often in two ranks, ascending, dense, short with blunt apices; in stem cross section a central strand developed; pseudoparaphyllia few, only on young branch bases, lanceolate, laciniate. Leaves dense, in two ranks; stem leaves squarrose, decurrent at base, slightly plicate, broadly triangular-cordate, abruptly narrowed to a slender apex, usually lanceolate, serrate; costae double, very short; leaf cells linear, often prorate; alar cells differentiated, oval or rounded quadrate to hexagonal, hyaline; branch leaves imbricately appressed when dry, erect-patent when moist, rounded ovate at base, gradually lanceolate, with short and twisted apices. Dioicous. Inner perichaetial leaves lanceolate, laciniate at margins, abruptly lanceolate at apex. Setae reddish purple, papillose, twisted when dry; capsules inclined or horizontal, oblong-ovoid, arcuate, reddish brown; opercula conic, shortly apiculate; annuli differentiated, deciduous; peristome double; exostome teeth lanceolate, yellowish green, united at base, bordered, hyaline and papillose above; trabeculate on the inner surface, sometimes not developed; endostome segments thin, narrowly lanceolate, perforate or completely separate, basal membrane low; cilia 2, nodulose. Calyptrae cucullate, smooth. Spores yellowish green, nearly smooth.