2. Barbula convoluta Hedw. 卷叶扭口藓 juan-ye niu-kou xian
Sp. Musc. Frond. 120. 1801. Tortula convoluta (Hedw.) Gaertn., Meyer & Scherb., Oekon. Fl. Wetterau 3(2): 92. 1802. Streblotrichum convolutum (Hedw.) P. de Beauv., Prodr. Aethéogam. 89. 1805. Type. Europe.
Barbula subconvoluta C. Müll., Nuovo Giorn. Bot. Ital., n. ser. 5: 183. 1898. Type. China: Shaanxi (Schen-si), Tui-kio-san, P. J. Giraldi 1812 (isotype H).
Plants small, less than 10 mm high, yellowish green, in dense tufts. Stems erect, usually irregularly branched, often radiculose at base. Leaves contorted when dry, erect-spreading when moist, oblong-elliptic to narrowly ligulate, obtusely acute to rounded obtuse; margins entire, slightly recurved in lower 1¤2–2¤3 the leaf length, sometimes undulate; costa stout, percurrent or ending below the apex; upper leaf cells small, rounded-hexagonal, rather thick-walled, obscure, multi-papillose; basal cells differentiated, irregularly rectangular, smooth, hyaline. Dioicous. Perichaetial leaves sheathing at base, inner perichaetial leaves highly convolute, obtuse at apex. Setae ca. 20 mm long, reddish yellow; capsules erect to suberect, oblong-ovoid; peristome teeth, filiform, twisted.