1. Heterocladium angustifolium (Dix.) R. Watan. 狭叶异枝藓 xia-ye yi-zhi xian
J. Jap. Bot. 35: 261. 1960. Rauia angustifolia Dix., Rev. Bryol. Lichénol. 7: 111. 1934. Types. China: Liaoning (Ryonei), Mt. Koô (Fenghuang), on trees, Kobayasi 3899b (holotype BM), on dead trees, Kobayasi 3900 (paratype BM).
Plants small, intricate, yellowish green, not glossy. Stems prostrate, 0.8–1.1 cm long, sparsely pinnately branched; branches ca. 4 mm long. Stem leaves small, appressed when dry, erect-spreading when moist, oblong-ovate-lanceolate or triangularly lanceolate, acuminate at apex, 0.40–0.45 mm × 0.10–0.15 mm; margins serrulate; costa inconspicuous; median leaf cells triangular to rhomboidal, 3–5 µm × 3–4 µm, thick-walled, smooth; apical cells oval, ca. 9 µm × 7 µm; branch leaves smaller, shortly ovate-lanceolate, ca. 0.15 mm × 0.10 mm. Dioicous. Perichaetial leaves ovate-lanceolate, sheathing at base, acuminate and falcate above, 1.5–2.0 mm × 0.5–0.6 mm; margins serrulate; costa single, slender; median cells oblong or rectangular, thick-walled; basal cells rectangular, smooth. Setae erect, reddish brown, ca. 9 mm long, smooth; capsules oblong-ovoid, symmetrical, brownish red, horizontal to nearly pendulous, neck short; opercula convex to shortly conic, reddish brown to brown; exothecial cells rhomboidal to hexagonal, thin-walled; annuli not differentiated; exostome teeth lanceolate, reddish brown, ca. 3 mm long, densely papillose above, cross-striolate below; endostome segments yellowish, narrowly lanceolate, nearly as long as the teeth, keeled; basal membrane ca. 1/2 the height of teeth; cilia short. Calyptrae cucullate, smooth. Spores pale yellowish, ca. 12 µm in diameter.