Plants evergreen, large. Rhizome erect, black-brown, robust, trunklike, apex densely scaly; scales brown, linear or linear-lanceolate, up to 2 cm, thickly membranous, margin toothed, with narrow black band; fronds caespitose. Fertile fronds up to 4 m; stipe brown at base, upward dark stramineous or light brown, robust, up to 2 m, up to 2 cm in diam., base densely scaly, scales similar to those on rhizome, upward with many stiff short aculeate protuberances, with similar processes on rachis; lamina 2-pinnate with pinnules pinnate, ovate-oblong, up to 2 × 1.4 m, apex acuminate; pinnae 24 pairs, alternate, ascending, broadly oblong-lanceolate, up to 85 × 25 cm, base truncate, stipe up to 7 cm, apex acuminate; pinnules up to 30 pairs, alternate or subopposite, spreading, nearly symmetrical; lower pinnules often shortly stalked, lanceolate or linear-lanceolate, up to 13 × 2.5 cm, base truncate, slightly asymmetrical (acroscopic lobe smaller), pinnatipartite to costa, apex acuminate; pinnule lobes or secondary pinnules up to 20 pairs or more, sickle-shaped oblong, slightly oblique, margin regularly serrate, apex rounded or subacute; veins visible, pinnate, veinlets simple, ascending, up to 14 pairs per pinnule lobe. Lamina stiffly papery when dry, usually gray-green, occasionally gray-brown, paler abaxially; rachis and costa stramineous or light brown, abaxial side with shortly aculeate protuberances, adaxially shallowly grooved, with light brown short hairs. Sori linear or suboblong, up to ca. 10 pairs per pinnule lobe, often single or double on basal acroscopic veinlets, costal-inframedial, from costule to 1/2 of veinlet length or longer, often contiguous when mature; indusia brown when mature, lacerate, membranous, opening acroscopically, persistent. Spores subreniform, perispore hyaline and wide, few rugate. 2n = 82.
Tropical mountain valleys, rain forests, beside streamlets; 300-1200 m. Hainan, Taiwan (Taidong), SE and SW Yunnan [Cambodia, S India, Indonesia, Laos, Malaysia, Myanmar, Papua New Guinea, Philippines, Sri Lanka, Thailand, Vietnam].