牛毛藓

Ditrichum homomallum (Hedw.) Hampe, Flora 50: 182. 1867. Didymodon homomallus Hedw., Sp. Musc. Frond. 105. 1801. Ditrichum subtortile Card., Bull. Herb. Boiss., sér. 2, 7: 716. 1907.

Plants small, up to 1.0 cm high, yellowish green, in loose tufts. Stems erect, simple. Leaves slightly homomallous, appressed when dry, erect-patent when moist, lanceolate, 2.0–3.5 mm long, abruptly narrowed from an ovate base to a long, setaceous acumen; margins plane and entire; costa stout, percurrent to short-excurrent, filling almost the entire subula; cells elongate throughout, rectangular to linear, 20–40 µm × 3–5 µm, rather thin-walled. Dioicous. Perichaetial leaves larger than the upper stem leaves, sheathing at base. Setae straight, 1.5–2.0 cm long, reddish brown; capsules erect, cylindric, nearly symmetric, ca. 2 mm × 0.3–0.4 mm, reddish brown, slightly contracted below the mouth; opercula short conic-rostrate; annuli in 2 rows of large, thick-walled cells; peristome teeth linear, 0.25–0.30 mm long, divided nearly to the base, whitish yellow, irregularly papillose. Spores 10–12 µm in diameter, yellow, nearly smooth.

Syntypes. Austria and Switzerland.

Chinese specimens examined: GUANGDONG: Chao-yang Co., X.-X. Huang & Z.-X. Li 11 (IBSC); Lian-ping Co., P.-J. Lin 1333 (IBSC). GUANGXI: Tian-lin Co., C. Gao 2401 (IFSBH). GUIZHOU: Gui-yang City, Y. Zhang 599 (IFSBH). HAINAN: C. Gao 2775 (IFSBH). JIANGXI: Lu Shan (Mt.), D.-K. Li 17348 (SHM). SICHUAN: Ya-an Co., C. Gao et al. 17470 (IFSBH). XIZANG: Mo-tuo Co., Y.-G. Su 4754 (KUN); Shejila Shan (Mt.), S.-K. Chen 359 (IFSBH). YUNNAN: Gong-shan Co., M.-Z. Wang 9361 (IFSBH, PE), D.-C. Zhang 1066 (KUN).

Habitat: on soil or rocks; Distribution: China, India, Korea, Japan, Europe, Alaska, and North and South America.

Illustrations: C. Gao (ed.) 1994 (Pl. 31, figs. 1–10).