普通铁线蕨 pu tong tie xian jue

Adiantum caudatum Linnaeus var. edgeworthii (Hooker) Beddome; A. caudatum var. rhizophorum Wallich ex C. B. Clarke; A. edgeworthii var. spencerianum (Copeland) Tagawa; A. guilelmi Hance; A. spencerianum Copeland.

Plants terrestrial, 10-30 cm tall. Rhizomes erect, short, scales black-brown lanceolate, margins denticulate. Fronds clustered; stipe dark purplish, glossy, 4-16 cm, base covered with scales, distally smooth; lamina 1-pinnate, linear-lanceolate in outline, 6-23 × 2-3 cm, base subattenuate, apex acuminate; rachis castaneous, with sparse reddish brown linear scales, smooth, apex often prolonged into a whiplike stolon and rooting to form new plantlets; pinnules 10-30 each side, opposite or alternate, if rachis prolonged into a whiplike stolon then upper pinnules gradually further apart from each other; stalk ca. 1 mm; several basal pairs of pinnules shorter and relatively broader than middle pinnules and slightly reflexed, middle pinnules horizontally spreading, dimidiate, 1-1.5 × 0.5-0.8 cm, papery, dark brownish or brownish green, both surfaces glabrous, base asymmetrical with acroscopic side truncate, lower and inner margins straight and entire, upper margin shallowly 2-5-lobed, apex acute or obtuse; segments suborbicular, entire or slightly undulate; upper pinnules progressively smaller distally, terminal pinnules subflabellate, base cuneate, upper margins divided; veins multidichotomously forked, visible on both surfaces. Sori 2-5 per pinna, borne at apex of segments; false indusia orbicular or oblong, membranous, upper margins flat and straight, entire, persistent. Perispore granular.

Shaded wet places, on rocks; 700-2500 m. Gansu, Guizhou, Hebei, Henan, Liaoning, Shandong, Sichuan, Taiwan, Xizang, Yunnan [Bhutan, N India, Japan, Malaysia, Myanmar, Nepal, Philippines, N Thailand, Vietnam].