10. Hydrogonium sordidum (Besch.) P.-C. Chen, Hedwigia. 80:239. 1941; Barbula sordida Besch., Bull. Soc. Bot. France 41: 80. 1894.
Plants grayish green, in dense tufts. Stems erect, densely foliate. Leaves contorted when dry, erect-spreading when moist, ovate-lanceolate, plicate in the lower half, rounded-obtuse to blunt or sometimes weakly apiculate at the apex; margins entire, plane or slightly revolute; costa stout, percurrent, papillose on the back; upper leaf cells quadrate to hexagonal, thin-walled, more or less mammillose; basal cells oblong. Sporophytes not seen.
Type. Vietnam: Hanoi, H. Bon 3615.
Chinese specimens examined: FUJIAN: Wuyi Shan (Mt.), D.-K. Li 11512 (HKAS, SHM). GUANGDONG: Guang-zhou City, X.-X. Chen 80018, 80020 (PE). SICHUAN: Wen-chuan Co., J.-X. Luo 3525 (PE). YUNNAN: Li-jiang Co., X.-J. Li 81–552 (HKAS); Lu-xi Co., X.-J. Li 41 (HKAS); Shun-ning, Q.-W. Wang 7390 (PE). ZHEJIANG: Hang-zhou City, D.-K. Li 205 (HKAS, SHM).
Habitat: on rocks or soil walls in shade or moist places; Distribution: China and Vietnam.
Illustrations: Pl. 124, figs. 8–9.