断线蕨 duan xian jue

Selliguea hemionitidea C. Presl, Tent. Pterid. 216. 1836; Colysis hemionitidea (C. Presl) C. Presl; Drynaria hemionitidea (C. Presl) J. Smith; Leptochilus decurrens Blume subsp. hemionitideus (C. Presl) Fraser-Jenkins; Microsorum ensato-sessilifrons (Hayata) H. Itô; M. hemionitideum (C. Presl) Copeland; Pleopeltis hemionitidea (C. Presl) T. Moore; Polypodium ensato-sessilifrons Hayata; P. hemionitideum (C. Presl) Wallich ex Mettenius.

Rhizome 2-4 mm in diam., dorsiventrally flattened; scales pseudopeltate, narrowly ovate or triangular, 2-4 × 0.7-1.2 mm, clathrate or subclathrate, central region bearing multiseptate hairs at least when young or glabrous, margin denticulate. Fronds not or only slightly dimorphic; stipe winged for a considerable part; lamina simple, narrowly ovate to narrowly obovate, 28-60 × 3-8.5 cm, thinly herbaceous, abaxial surface without acicular hairs, base very narrowly cuneate, margin entire, apex acute or acuminate; lateral veins ± straight, prominent and distinct, (6-)7.6-14 mm apart, dichotomously branched near margin, connecting veins 4-7 between adjacent veins, anadromous, veinlets generally forming 2-4 prominent and distinct areoles, free veinlets simple or once forked. Sori orbicular or elongate, in 1 discontinuous line between each pair of veins, superficial or slightly sunken, absent from basal 30%-50% of lamina, 1-4(-7) per veinlet.

Terrestrial on stones in streams, in dry evergreen forests, on wet ground in stream beds in dense forests, locally common; 700-2000 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Jiangxi, Sichuan, Taiwan, Xizang, Yunnan [Bhutan, India, Japan, Nepal, Thailand].

The epithet was first introduced by Wallich as Polypodium hemionitideum (Numer. List, no. 284. 1829, nom. nud.).