4. Oligotrichum obtusatum Broth. 钝叶小赤藓 dun ye xiao chi xian
Symb. Sin. 4: 133. 1929. Type: China. Yunnan Prov., between Dali and Hodjing, Handel-Mazzetti 6505 (holotype H).
Plants rather small, 0.5–1.2 cm high, brownish green to reddish brown, often in tufts. Leaves nearly oblong-oval, 1.5–2.0 mm × 0.5–1.0 mm, usually concave; margins serrate; costa somewhat broad, ending near the apex; ventral lamellae slightly wavy or crisped, usually in 3–10 rows, 3–5 cells high; on leaf back with only a few spines; median leaf cells rounded quadrate to irregularly oval, 9–15 µm wide; basal cells elongate or irregularly rectangular, 18–25 µm × 8–16 µm, slightly thick-walled. Dioicous. Perichaetial leaves lanceolate above, sheathing at base. Setae reddish brown, straight; capsules oblong-ovoid to shortly cylindrical, usually curved; peristome teeth 32; opercula conic, shortly beaked. Calyptrae cucullate, smooth. Spores spherical, ca. 10 µm in diameter, finely papillose.