威氏石灰藓

Plants small, to 15 mm high, yellowish green, in dense tufts. Stems erect, simple or branched. Leaves contorted when dry, erect-spreading when moist, usually concave, narrowly lanceolate, blunt or rounded-obtuse at the apex; margins entire, plane; costa stout, ending just below the apex; upper leaf cells very small, quadrate to pentagonal, or irregularly rectangular, thick-walled, smooth; basal cells oblong-rectangular, more than 10 times longer than the upper cells. Setae slender, ca. 15 mm long, reddish brown; capsules erect, oblong-elliptic ovoid; peristome teeth linear, twisted.

Type. The Philippines: Luzon, Bagnio, 1500 m, Williams 1673.

Chinese specimens examined: SHANDONG: Tai Shan (Mt.), C. Gao 33949, 33954 (HKAS, IFSBH). SHANXI: Tai-yuan City, Y.-J. Ling 59008 (HKAS). XIZANG: Mo-tuo Co., Y.-G. Su 2268 (HKAS); Zhong-ba Co., K.-Y. Lang 7578 (HKAS). YUNNAN: De-qin Co., X.-J. Li 81–1841 (HKAS); Lv-chun Co., M. Zang 421 (HKAS); Yuan-yang Co., X.-J. Li 4913 (HKAS); Zhong-dian Co., X.-J. Li 81–1479, 81–1486 (HKAS).

Habitat: on calcareous rocks or on wet rocks near streams; Distribution: China and the Philippines.

Illustrations: Zander 1993 (Pl. 45, figs. 13–15, as Barbula williamsii).