高山大帽藓

Encalypta commutata Nees, Hornsch. & Sturm, Bryol. Germ. 2: 46. 1827. Encalypta giraldii C. Müll., Nuov. Giorn. Bot. Ital., n. ser. 5: 173. 1898. Type. China: Shaanxi (Schen-si), Mt. Tui-kio, X 1896, Giraldi s.n. (lectotype H-BR).

Plants medium-sized to large, sometimes robust, 1.0–3.0 cm high, yellowish green above, brown below, in dense tufts. Stems simple or sparsely branched; central strand not well developed. Leaves slightly twisted when dry, erect-spreading when moist, 2.8–3.5 mm long, ovate-lanceolate to narrowly ovate-lanceolate, tapering gradually to the apex, with a short or long apiculus; margins plane; costa single, strong, excurrent; upper cells small, irregularly quadrate, 10–13 µm wide, with dense papillae, obscure; basal cells oblong to elongate, 40–53 µm x 10–15 µm, with reddish brown, thickened transverse walls, basal marginal cells linear, of 3–5 rows, 57–58 µm x 5–8 µm, thin-walled. Autoicous. Perichaetial leaves similar to upper stem leaves. Setae reddish, 7–10 mm long, erect, twisted above when dry; capsules erect, cylindric to narrowly cylindric, 2–3 mm long, smooth or nearly so; peristome absent; annuli undifferentiated; opercula with a long, erect beak. Calyptrae large, golden brown, cylindric to narrowly cylindric, with a short rostrum, about 1/4–1/3 the length of calyptra, lacerate at the base. Spores 30–33 µm in diameter, yellowish brown, irregularly papillose.

Type. Scotland: Ben Lawers, October 1804, G. Don s.n. (lectotype BM).

Chinese specimens examined: HEBEI: Xiao-wu-tai Shan (Mt.), Y.-C. Zhao 28 (IFSBH). QINGHAI: Cheng-duo Co., B.-C. Tan 95-1660 (FH, MO); Nang-qian Co., B.-C. Tan 95-1653 (FH, MO). SHAANXI: Tai-bai Shan (Mt.), Z.-P. Wei 5643 (IFSBH); Tui-kio Shan (Mt.), Girald 1988 (H-BR). SICHUAN: Hong-yuan Co. (Wagen to Mewa Hwy.), Allen 7049 (MO). XINJIANG: Arjin Shan (Mt.), Achuff 7238 (ALTA, IFSBH); Urumqi Co., S. He 951093 (MO). XIZANG: An-duo Co., D.-D. Tao 2104a (IFSBH), M. Zang 5304a (HKAS). YUNNAN: west boulder, Handel-Mazzetti 1228 (H-BR).

Habitat: in montane areas on soil or thin soil over rocks and in fens; Distribution: China, Japan, Mongolia, Middle Asia, Europe, and North America.

Encalypta alpina is distinguished by 1) leaves with a somewhat sheathing, ovate or oblong base that gradually narrows to an acute apex and with a stout, short or long apiculus; 2) calyptrae with a relatively short rostrum, only ca. 1/5 the total length of the calyptra; 3) peristome absent and annuli undifferentiated; and 4) spores irregularly papillose with proximal and distal surfaces hardly differentiated.

There is variation in the leaves of some Chinese populations of E. alpina from the Arjin Mountains Nature Reserve. Individual plants have some leaves that are characteristically apiculate, but others are muticous. The sporadic occurrence of populations of E. alpina with stunted plants and uniformly muticous leaves has been noted (Horton 1983), and it was suggested that these are developmental aberrations or environmental modifications. The variation in the Chinese populations differs from that previously described, because it occurs on individual plants, and these are well developed, although some are rather heavily encrusted with calcareous deposits that might make them more fragile. The leaves in a third population from this same area are consistently apiculate.

Illustrations: Cao, Horton & Gao 1992 (fig.1, 1–8).