水丝麻 shui si ma

Boehmeria puya Hooker, Hooker’s J. Bot. Kew Gard. Misc. 1: 26. 1849; B. esquirolii H. Léveillé; B. nivea var. crassifolia C. H. Wright.

Shrubs 1-2 m tall, monoecious. Branchlets zigzagged, branchlets and petiole spreading, brown or gray-brown hirtellous. Stipules linear-lanceolate, 7-15 mm, 2-cleft; petiole 1-6 cm; leaf blade elliptic or ovate, 5-15 × 3-7 cm, secondary veins 2-4 on each side from distal 1/3, sparsely appressed strigose, adaxially rugose, thickly, snow white tomentose abaxially, base broadly cuneate or rounded, margin coarsely dentate, apex acuminate. Cymes in pairs, 3-5 cm; glomerules lax, 2-3 mm in diam.; bracts triangular or lanceolate, membranous. Male flowers shortly pedicellate, obovoid in bud, 1 mm in diam.; perianth lobes 5, ovate, connate at middle, apex acuminate; rudimentary ovary trigonous-ovoid, ca. 0.4 mm. Female flowers sessile; perianth lobes 2, minute, unequal, ± connate at base, enclosing base of ovary. Achene ovoid-trigonous, ca. 1.2 mm, appressed strigillose. Fl. Jun-Aug, fr. Sep-Oct.

Thickets, valleys, dry slopes or shady, wet places; 400-2000 m. Guangxi, Guizhou, SW Sichuan, SW Xizang, Yunnan [Bhutan, NE India, Nepal, Sikkim, Vietnam].

Fiber from the stem bast is of high quality due to its strength, sheen, and length; a single fiber may be 18 cm long. The fibers are used to make cloth, fishing nets, and paper.