Plants 3-8 cm, in dense erect cushions or prostrate mats, green, yellow-green, or fuscous green. Stems yellow; cross section pentagonal, cortical cells in 2-5 irregular layers, medulla cell walls thick to thin, central strand present; rhizoids usually covered by leaves except in older parts of plants. Leaves imbricate, not twisted when dry or moist, oblong to elliptic, widest above base, concave; base not rounded or narrowed to insertion; margins revolute 1-2 times to just before apex, entire; apex rounded-cucullate; costa flexuose toward apex; laminal cells round to oblong, papillae low; basal cells usually 2-stratose, often brown. Specialized asexual reproduction absent. Perigonia as terminal discoid splash platforms; paraphyses of 6-9 cells. Perichaetia with paraphyses absent. Seta 0.2-0.3 cm. Capsule horizontal, 3-5 mm; operculum conic, rostrum short, blunt; endostome cilia nodose. Spores 8-13 µm, smooth.
4. Aulacomnium turgidum (Wahlenb.) Schwaegr. 大皱蒴藓 da zhou shuo xian Sp. Musc. Frond., Suppl. 3(1): 7. 1827. Sphaerocephalus turgidus Lindb., Musci Scand. 14. 1879. Gymnocybe turgida (Wahlenb.) Lindb., Not. Sällsk. Fauna Fl. Fenn. Förh. 9: 85. 1868. Mnium turgidum Wahlenb., Fl. Lapp. 351. 1812. Type: Europe. Plants rather large, yellowish green, in dense tufts. Stems thick, erect, 5–8 cm high, branched, with sparse rhizoids at base. Leaves imbricate, oblong or elliptical, 1.5–2.4 mm × 0.8–1.2 mm, strongly concave, rounded-cucullate at apex; margins plane, entire; costae more or less flexuous above, ending below the apex; upper leaf cells nearly isodiametric, thick-walled, unipapillose on both sides; basal leaf cells at the insertion rectangular, inflated, bi- or tri-stratose, smooth. Dioicous. Setae straight, ca. 2.0–2.8 cm long; capsules elongate-ovoid, slightly curved, ca. 2.0–2.5 mm long, inclined to horizontal; opercula shortly rostrate; peristome double; exostome teeth lanceolate, yellowish, densely papillose; endostome segments keeled, perforate, hyaline; basal membrane high; cilia 2–3, nodulose. Spores spherical, yellowish, 10–15 µm diameter, smooth.