4. Brachythecium buchananii (Hook.) A. Jaeger 多褶青藓 duo zhe qing xian Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1876–77: 341. 1878. Hypnum buchananii Hook., Trans. Linn. Soc. London 9: 320, pl. 28. f. 3. 1808. Type: India. Brachythecium carinatum Dixon, Rev. Bryol. Lichénol. 7: 114. 1934. Platyhypnidium microrusciforme (Müll. Hal.) M. Fleisch., Musci Buitenzorg 4: 1537. 1923. Rhynchostegium microrusciforme Müll. Hal., Nuovo Giorn. Bot. Ital., n.s., 5: 202. 1898. Type: China. Shaanxi, Giraldi s.n. Plants medium-sized. Stems prostrate, 4–5 cm long, irregularly branched, attenuate at branch tips. Stem leaves ovate, 1.71–2.30 mm × 0.79–0.90 mm, gradually or rather abruptly acuminate toward apex, often deeply 3–4-plicate; margins entire, slightly reflexed near leaf bases; costae ending just above mid-leaf; branch leaves smaller, 1.26–1.35 mm × 0.45–0.54 mm; median leaf cells linear, 72–105 µm × 9–10 µm, with angled ends, thin-walled; basal cells broader, elongate-rhomboidal, somewhat thick-walled; alar cells nearly quadrate or shortly rectangular. Dioicous. Setae 10–20 mm long, smooth throughout; capsules inclined, elongate-ellipsoidal, neck distinctly developed; opercula conic-rostrate; peristome double; endostome segments as long as the exostome teeth; cilia 2, well developed, nodulose, nearly as long as the segments. Spores not seen.