1. Atrichum P. Beauv. 仙鹤藓属 xian he xian shu
Mag. Encycl. 5: 329. 1804. Polytrichum subgen. Atrichum (P. Beauv.) Wils. in Hook., Fl. Nov.-Zel. 2: 94. 1854. Callibryon Zenk. & Dietr., Musci Thur. 11: 41. 1822, nom. illeg. Catharinea Ehrh. ex Web. & Mohr, Observ. Bot. 31. 1803.
Plants small to medium-sized, rigid, erect, green, dark green or brownish green, usually in loose tufts. Stems single or rarely branched; rhizoids often numerous at base; central strand developed. Leaves lanceolate or lingulate, acuminate or acute, often obliquely undulate, spines obliquely arranged on leaf back, strongly curved or crisped when dry, erect-patent when moist, loosely or densely foliate on stems above; leaf cells usually smooth, median cells mostly rounded quadrate or hexagonal, lower cells rectangular; margins bordered by 1–3 rows of elongate or linear cells, often double-toothed; costa single, reaching leaf apex or excurrent; lamellae only growing on the ventral surface of the costa, usually consisting of uniform cells. Dioicous, rarely monoicous. Setae slender, erect; capsules single or tufted, cylindrical, erect or slightly vaulted, apophyses small or undeveloped; peristome teeth single, 32, reddish brown, keeled; opercula conic, long beaked. Calyptrae cucullate. Spores yellowish green, minutely papillose.