1. Aulacopilum abbreviatum Mitt. 圆钝苔叶藓 yuan dun tai ye xian
J. Linn. Soc. Bot. 13: 308. 1873. Erpodium abbreviatum (Mitt.) I. G. Stone, J. Bryol. 19: 488. 1997. Type: India.
Plants small, bright green, in loose or dense mats. Stems prostrate, 5–8(–10) mm long, irregularly branched; leafy stems less than 0.6 mm wide when dry, sometimes with purple reddish rhizoids on ventral surface. Leaves imbricate when dry, spreading when moist; dorsal and ventral leaves slightly dimorphic; ventral leaves smaller, symmetric; median and upper leaf cells nearly hexagonal, 25–57 µm × 15–25 µm, papillose, each cell with 3–6(–8) papillae, slightly thick-walled; alar cells subquadrate; dorsal leaves broadly ovate-lanceolate, 1.0–1.5 mm × 0.2–0.3 mm, asymmetric, shortly acute at the apex; margins entire; costae none. Autoicous. Perichaetial leaves, 1.0–2.5 mm long. Setae slightly elongate, yellowish; capsules somewhat exserted, ovoid, 1.0–2.5 mm long; opercula conic at the base, shortly rostrate; annuli not developed; peristome highly reduced or absent. Calyptrae large, covering the entire capsules. Spores 15–25 µm in diameter, densely minutely papillose.