1. Oligotrichum aligerum Mitt. 高栉小赤藓 gao zhi xiao chi xian
J. Proc. Linn. Soc., Bot., 8: 48. f. 8. 1864. Type: Japan.
Plants small, 0.5–1.5 cm high, male plants generally smaller than female ones, brownish green to reddish brown, erect, usually tufted, rarely scattered. Stems with poorly developed central strand; rhizoids numerous at the base. Leaves lanceolate, slightly sheathing at base, often clasping by the base; upper leaves often crisped when dry, erect-patent when moist; middle leaves 2.5–3.5 mm × 0.3–0.5 mm; margins serrate or serrulate; costa rather broad, often reaching leaf apex; ventral lamellae 6–9 rows, slightly wavy, usually 5–10 cells high; the lamellae of upper leaves low, 2–5 cells high; leaf cells unistratose, median cells rounded ovate or rounded quadrate, 10–15 µm wide, basal cells rather long or nearly rectangular, 25–50 µm × 10–15 µm, rather thin-walled. Dioicous. Perigonia in rosettes, often growing new innovations from center. Setae reddish brown, straight; capsules oblong-ovoid, asymmetrical, usually single; peristome teeth 32, membrane low; opercula shortly cylindrical, with short beaks. Calyptrae cucullate, smooth, often with short cilia on apex. Spores spherical, 10–13 µm in diameter, verrucose.