疏叶石毛藓

Didymodon laxifolius (Hook.f.) Mitt., J. Proc. Linn. Soc., Bot. Suppl. 1: 23. 1859. Zygodon schmidii C. Müll., Bot. Zeit. 11: 60. 1853. Oreoweisia schmidii (C. Müll.) Paris, Index Bryol. 868. 1897.

Plants soft, rather large, to 5 cm high, yellowish green above, dark green below, not shiny, in dense tufts. Stems erect, often dichotomously branched. Leaves laxly spaced, curled when dry, erect-patent when moist, oblong-lingulate, up to 2.5 mm × 0.6 mm, somewhat sheathing at base, obtuse or blunt at apex; margins plane, irregularly serrulate near the apex; costa narrow, percurrent, with dorsal stereid band; upper cells quadrate to rounded-quadrate, thick-walled, mammillose on both surfaces; basal cells rectangular, ca. 60 µm × 18 µm, pellucid, thin-walled; alar cells not differentiated. Autoicous. Perichaetial leaves similar to upper stem leaves. Setae straight, orange-brown, ca. 10 mm long, twisted when dry; capsules reddish brown, erect, oblong-ovoid to short-cylindric, symmetric, contracted near the mouth, urns ca. 3 mm × 1 mm, exothecial cells rather thin-walled; peristome teeth inserted below the mouth, yellowish, smooth. Spores brownish, 18–20 µm in diameter, warty.

Syntypes. India: Sikkim, J. D. Hooker 103, 104, 105, 107.

Chinese specimens examined: GUANGXI: Xing-an Co., C. Gao & G.-C. Zhang 1703 (IFSBH). HEBEI: Xing-long Co., J.-X. Ji 752 (IFSBH). LIAONING: Ben-xi Co., C. Gao & G.-C. Zhang 83400 (IFSBH). SICHUAN: Omei Co., Raven et al. 56 (MO); Hui-li Co., Handel-Mazzetti 956, 968 (H). XIZANG: Cuo-na Co., S.-K. Chen 5162 (IFSBH, KUN); Ya-dong Co., M. Zang 598 (IFSBH, KUN). YUNNAN: Da-li Co., Handel-Mazzetti 6496, 6597 (H); Yang-bi Co., Redfearn et al. 455, 675 (MO).

Habitat: on soil and rocks, rarely on rotten wood in forests; Distribution: China, Himalayas, India, and Japan.

Illustrations: Pl. 55, figs. 1–9.