Hemionitis opaca D. Don, Prodr. Fl. Nepal. 13. 1825; Athyrium opacum (D. Don) Copeland; Diplazium opacum (D. Don) Christ; Dryopteris bankinsinensis Hayata; D. opaca (D. Don) C. Christensen; D. succulentipes Hayata; Gymnogramma obtusata Blume; G. opaca (D. Don) Sprengel; Leptogramma obtusata (Blume) J. Smith; L. opaca (D. Don) Beddome; Nephrodium obtusatum (Blume) Diels (1899), not C. Presl (1825); Phegopteris obtusatum (Blume) Christ; P. opaca (D. Don) Mettenius.

Plants evergreen. Rhizome short, ascending or erect, apex with brown, lanceolate or broadly lanceolate scales; fronds caespitose. Fertile frond up to 120 cm; stipe dark stramineous (often dark brown when dry), 20-50 cm, base with sparse scales, scales upward deciduous; lamina 1- or 2-pinnate, deltoid-ovate, 30-60 × 20-30 cm, base rounded-cuneate, apex acuminate; pinnae ca. 10 pairs, stalked (stalk up to 3 mm), subopposite, slightly ascending or sometimes subspreading; basal pinnae not shortened or slightly shortened, 10-20 × 4-15 cm, elliptic, base subtruncate, pinnatilobate to pinnate, apex long acuminate; pinnules up to 10 pairs, alternate, spreading, elliptic or elliptic-lanceolate, up to 9 × 2.5 cm, pinnatifid to pinnatisect, base truncate, sessile or subsessile, apex acuminate or obtuse; basal pinnules much shorter, apex rounded; pinna lobes subelliptic or rectangular, entire, subtruncate or rounded at apex; veins visible abaxially, veinlets simple or upper veinlets forked, ascending. Lamina herbaceous; rachis, costae, and costules abaxially with multicellular short nodose hairs, or glabrous, also with sparse linear, brown, entire scales. Sori brown, shortly linear or elliptic, medial or inframedial, 1-3 pairs per pinna lobe. Spores subreniform, perispore prominent, projections few rugate. x = 40.

Cornopteris opaca is variable in the shape and dissection of the fronds and differs from C. decurrenti-alata primarily in the rhizome habit.

Plants having a glabrous rachis, costa, and midribs, particularly in old fronds, have been named Cornopteris opaca f. glabrescens Sa. Kurata (J. Geobot. 12(2): 41. 1963; 变光黑叶角蕨 bian guang hei ye jiao jue): evergreen broad-leaved forests; 800-1800 m. Fujian, Guangxi, Taiwan, Yunnan [Indonesia, Japan, Vietnam].

Evergreen broad-leaved forests; 400-2300 m. Fujian, Guangxi, Jiangxi, Taiwan, Yunnan [Bhutan, India, Indonesia, Japan, Nepal, Vietnam].