25. Adiantum venustum D. Don, Prodr. Fl. Nepal. 17. 1825.
细叶铁线蕨 xi ye tie xian jue
Adiantum venustum var. wuliangense Ching & Y. X. Lin.
Plants terrestrial, 25-50 cm tall. Rhizomes decumbent, thick, scales dense, dark brown, ovate-lanceolate, margins entire. Fronds remote; stipe castaneous-brown, 10-20 cm, base covered with same scales as rhizome, distally glabrous; lamina 3-pinnate, broadly ovate in outline, 10-25 × 5-12 cm, apex acuminate and 1-pinnate; pinnae ca. 6 each side, obliquely spreading, stalks 2-7 mm; rachises, costae, and stalks ± zigzag, same color as stipe, glabrous; basal pair of pinnae largest, 2-pinnate, ovate-elliptic, 5-13 × 4-7 cm; pinnules 4 or 5 pairs per lateral pinna, alternate, upwardly oblique, shortly stalked, flabellate, 7-10 × 7-10 mm, green or brown-green, herbaceous, both surfaces glabrous, base shortly cuneate, shortly stalked, apex rounded and denticulate. Veins multidichotomously forked, reaching teeth at pinnule margin, visible on both surfaces. Sori 1 or 2(or 3) per pinnule, attached at rounded sinus; false indusia brownish, orbicular, membranous, upper margin deep sinuslike, entire, persistent. 2n = 120.
Rock crevices, mountain slopes; 2000-2900 m. Xizang, Yunnan (Jingdong, Wuliang Shan) [Bhutan, India, Kashmir, N Myanmar, Nepal].