20. Trichosteleum Mitt. 刺疣藓属 ci you xian shu
J. Linn. Soc., Bot. 10: 181. 1868. Hypnum subsect. Trichosteleum (Mitt.) C. Müll., Linnaea 39: 465. 1875.
Plants slender or robust, green or yellowish green, rarely yellowish or yellowish brown, not glossy or somewhat glossy. Stems prostrate, elongate, with rhizoids, densely irregularly branched or subpinnately; branches simple or rarely with short branchlets, more or less blunt at apex. Leaves not dimorphic, erect or erect-spreading, sometimes falcate-secund, spathulately concave, not plicate, lanceolate, oblong-lanceolate or oblong-elliptic, rarely ovate, constricted from the middle into a narrowly long acuminate apex; margins usually reflexed, serrate above; costae absent; leaf cells oblong-oval or narrowly rhomboidal, often thin-walled, rarely thick-walled, pitted; alar region consisting of a few inflated, oblong-oval, hyaline or yellowish cells. Autoicous. Inner perichaetial leaves erect, narrowly lanceolate; margins serrulate; costae absent; cells smooth. Setae thin, short, curved near capsules, usually coarse above, rarely smooth; capsules usually pendent, small, asymmetric; exothecial cells strongly collenchymatous, often mammillose; opercula conic, very slenderly long-rostrate; annuli absent; peristome double; exostome teeth narrowly lanceolate, with a zigzag median line on outer surface, cross-striate below, papillose above; inner surface clearly trabecualte; endostome segments as high as the teeth, yellowish, papillose, keeled, perforate; basal membrane high; cilia usually 1, slightly nodulose, sometimes reduced. Calyptrae cucullate, smooth or coarse above. Spores small, spherical, green, papillose.