1. Rhabdoweisia crenulata (Mitt.) Jameson, Rev. Bryol. 17: 6. 1890; Didymodon crenulatus Mitt., J. Proc. Linn. Soc., Bot., Suppl. 1: 23. 1859.
Plants small, up to 10 mm high, dull green to yellowish green, in dense tufts. Stems erect, usually unbranched, reddish brown; central strand absent. Leaves crispate when dry, erect-patent to spreading when moist, 2–3 mm long, oblong-lanceolate to narrowly lingulate, leaf base not clearly narrower, the upper part gradually narrowed from the middle, broadly acute at the apex; margins serrate in the upper 1/3 or more; costa light brown, subpercurrent; upper cells subquadrate, 13–16 µm wide, subobscure; lower cells rectangular, more or less hyaline, becoming longer near the costa; alar cells not differentiated. Setae elongate and straight, upper part twisted when dry, ca. 5 mm long, light brown; capsules erect, ovoid, yellowish brown; opercula obliquely long-rostrate; annuli none; peristome teeth yellowish brown, erect when dry, lanceolate, broader at the base, distinctly and obliquely striolate. Spores 18–21 µm in diameter, brownish, papillose.
Type. India: Sikkim, J. D. Hooker 270.
Chinese specimen examined: TAIWAN: Nan-tou Co., S.-H. Lin s.n. [Bryophytes of Taiwan Exsiccatae 142] (MO).
Habitat: on rock crevices; Distribution: China, India, Japan, Europe, Greenland, and North America.
Illustrations: C. Gao (ed.) 1994 (Pl. 92, figs. 8–15).