16. Adiantum myriosorum Baker, Bull. Misc. Inform. Kew. 1898: 230. 1898.
灰背铁线蕨 hui bei tie xian jue
Adiantum myriosorum var. recurvatum Ching & Y. X. Lin; A. pedatum Linnaeus var. glaucinum Christ; A. pedatum var. myriosorum (Baker) Christ; A. pedatum var. protrusum Christ.
Plants terrestrial, 40-60 cm tall. Rhizomes erect or ascending, scales dark brown, broadly lanceolate, margins entire. Fronds clustered or approximate; stipe nearly black, 12-25 cm, covered with same scales as rhizome, distally glabrous; lamina pedately dichotomous, broadly flabellate in outline, 25-35 cm; pinnae 3-7 per branch, 1-imparipinnate, linear-lanceolate in outline, outer pinnae progressively shorter; rachises and stalks glabrous; pinnules 20-30 pairs per pinna, alternate, obliquely spreading, stalked; basal pinnules slightly smaller, flabellate or semi-orbicular, with longer stalks; middle pinnules dimidiate, triangular-elliptic, ca. 2 × 0.6 cm, herbaceous, abaxially glaucous, both surfaces glabrous, base asymmetrical, cuneate, inner and lower margins straight and entire, upper margin lobed, apex obtuse; segments ± square, with acute triangular teeth; distal pinnules similar to middle pinnules but gradually smaller toward apices, terminal pinnules flabellate, divided at middle, bilateral sides lobed, equal in size or slightly larger than middle pinnules; veins multidichotomously forked, reaching margin, visible on both surfaces. Sori 4-6 per pinnule, horizontally attached in shallow sinuses; false indusia grayish green or dark brown, orbicular-reniform, membranous, entire, persistent. Perispore reticulate.
Dense forests; 900-2600 m. Anhui, Gansu, Guizhou, Henan, Hubei, Hunan, Shaanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, NE India, Kashmir, N Myanmar, Nepal].
Adiantum myriosorum is a beautiful plant that is cultivated as an ornamental.