下延叉蕨 xia yan cha jue

Aspidium decurrens C. Presl, Reliq. Haenk. 1: 28. 1825; A. copelandii C. Christensen; A. heterodon Copeland (1905), not Schrader (1824), nor Blume (1828); A. pteropus Kunze; Cardiochlaena alata Fée; Nephrodium decurrens (C. Presl) Baker; Sagenia decurrens (C. Presl) T. Moore; S. mammillosa T. Moore; S. pteropus (Kunze) T. Moore; Tectaria peralata Copeland; ?T. simulans Ching.

Plants terrestrial, 50-100 cm tall. Rhizome erect, short, thick, 1.5-2 cm in diam., densely scaly; scales stiff, brown, with pale ferruginous margins, 8-12 cm, entire, apices acute. Fronds clustered, dimorphic; stipe brown at base, stramineous upward, 35-60 cm, glabrescent above, winged nearly to base. Lamina deeply pinnately incised, deep green, oblong-ovate, 30-80 × 30-40 cm, thickly papery, both surfaces glabrous, base cuneate and long decurrent, apex acute, lobes narrowed in fertile fronds; rachises winged throughout, stramineous; costae and main veins raised abaxially; apical pinnae broadly lanceolate, 20-25 × 5-8 cm, gradually narrowing toward base, subentire or crenulate, apices caudate; lateral pinnae 3-8 pairs, opposite, ascending, broadly lanceolate, 15-20 × 3-5 cm, subentire or crenulate, apices caudate, interval 3-4 cm, narrowing toward base and coadnate to rachis, sessile, usually forked in each basal pinna. Veinlets forming hexagonal areoles, cross veins not distinct, included veinlets forked. Sori large, close to main veins, located at coupling veinlets, in 2 rows between adjacent main veins; indusia up to 1.2 mm in diam., glabrous, entire, persistent. 2n = 160.

On rocks or near streams in dense forests; below 1200 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Taiwan, Yunnan [India, Indonesia, Japan, Myanmar, Nepal, Philippines, Thailand, Vietnam].