毛叶铁线蕨 mao ye tie xian jue

Adiantum pedatum G. Forster (1786), not Linnaeus (1753); A. pubescens Schkuhr.

Plants ca. 40 cm tall. Rhizomes erect, short, scales purple-black, lanceolate, margins subentire. Fronds clustered; stipe dark castaneous, glossy, ca. 20 cm, ca. 2 mm in diam., densely brownish villous, glabrescent; lamina dichotomously 2- or 3-pinnate, broadly ovate-triangular in outline, ca. 18 × 10 cm, middle pinnae usually longest, 1-imparipinnate, linear-lanceolate in outline, ca. 16 cm; costae and stalks castaneous, densely brown pubescent; pinnules ca. 30 pairs per pinna, alternate, obliquely spreading, shortly stalked, lower 1 or 2 pairs of pinnules slightly reduced, flabellate or flabellate-rectangular, middle pinnules nearly uniform in size, orbicular, ca. 8 × 4-5 mm, papery, dark brown or deep olive-green, both surfaces sparsely brown pubescent, base asymmetrically cuneate, inner and lower margins straight and entire, with narrow shallow sinuses, outer margins rounded, upper margins rounded-truncate, sterile parts undulate and dentate; all lateral pinnae same shape as middle pinnae and gradually becoming shorter toward bilateral sides; fertile segments truncate and entire on upper margins, distal pinnules gradually smaller toward apex; terminal pinnules obtriangular, slightly larger than lower lateral ones; veins multidichotomously forked, visible on both surfaces. Sori 4-12 at sinuses of pinnules; false indusia dark brown, orbicular, leathery, pubescent adaxially, upper margins deeply depressed or sinuate, entire, persistent. 2n = 360.

Steep forested slopes, on rocks; 300-1500 m (in Taiwan). E Guangdong, E Taiwan, SE Yunnan [India, Indonesia (Java), Malaysia, Philippines; tropical and subtropical regions: Africa, Asia, Pacific islands].