黑足金粉蕨 hei zu jin fen jue

Onychium japonicum (Thunberg) Kunze var. intermedia C. B. Clarke; O. japonicum var. multisecta C. B. Clarke.

Rhizomes long creeping; scales dark brown, lanceolate. Fronds monomorphic, closely or widely spaced. Stipe (15-)20-50 cm × 2-3 mm, straw-colored above a black base. Lamina ovate to ovate-deltoid or often broadly ovate, (12-)20-38 × 10-26 cm, apex acuminate, finely 4-pinnate-pinnatifid, thinly papery when dry, green to grayish green, not farinose. Lateral pinnae 10-14 pairs, basal pair largest, ovate-deltoid, apex acuminate, 10-25 × 5-14 cm, stalked to ca. 1 cm. Ultimate pinnules (segments) not overlapping, linear to narrowly oblanceolate, narrowly oblong, or narrowly elliptic, 2-5 × 0.5-1.5 mm wide, margins often cartilaginous, entire or with 1 or 2 sharp teeth, base cuneate, decurrent, apex acute to slightly acuminate. Sori 1-3 mm. False indusia linear to oblong, extending nearly to midvein, entire. 2n = 87, 116.

Open woods, stream banks, valleys, often forming large, dense, clonal colonies; 1200-3500 m. S Gansu, Guizhou, Sichuan, Taiwan, S Xizang, NW Yunnan [Bhutan, Cambodia, India, Laos, Myanmar, Nepal, Thailand, Vietnam].

The Onychium cryptogrammoides group is a polyploid complex that requires further study. Onychium cryptogrammoides resembles O. japonicum but differs in its black stipe bases, finely divided lamina, and more slender costae and costules. The two species have different distributions. The name O. contiguum Wallich ex C. Hope has been applied to this taxon in much of the literature on Asian pteridophytes, but that epithet is a nom. illeg. superfl. for the taxon here treated as O. japonicum var. lucidum, as the basionym Leptostegia lucida D. Don was cited in synonymy in the protologue.