掌叶线蕨 zhang ye xian jue

Gymnogramma digitata Baker, J. Bot. 28: 267. 1890; Colysis digitata (Baker) Ching; C. digitata f. annamensis (Christ) Ching; C. digitata f. cadieri (Christ) Ching; C. digitata f. laciniata Ching; C. triphylla Ching & Chu H. Wang; Polypodium ampelideum Christ; P. annamense Christ; P. cadieri Christ; P. digitatum (Baker) C. Christensen; P. podopterum Christ.

Rhizome slender, long creeping, 3-5 mm in diam.; scales narrowly ovate or triangular, 1.5-6.6 × 1-1.7 mm, margin denticulate, apex long acuminate to hairlike. Fronds not or only slightly dimorphic; stipe stramineous, 20-30 cm; lamina pedately divided, trifid, unequally trifid, or simple, 8-18 × 8-26 cm, widest below middle, thinly herbaceous, base cuneate-decrescent to cuneate, margin entire or undulate; longest lobes widest below middle; apical lobe 10-18 × 1.5-4 cm; veins ± sunken and indistinct, or prominent and distinct, free included veinlets simple or once forked. Sori linear, 1 row between each pair of lateral veins, superficial or slightly sunken, on whole surface of lamina.

On rocks by streams, or climbing on lower tree trunks; sea level to 1400 m. Guangdong, Guangxi, Guizhou, Hainan, Yunnan [Vietnam].

Rarely, some or all of the fertile fronds of Leptochilus digitatus have very narrow linear lobes; sometimes simple leaves occur.