Rhizome prostrate, stout, densely covered with shiny brown long hairs. Stipes thick, up to 1 m or more, triangular in transverse section at base, with dense caducous appressed hairs, stipe and rachis green, turning purplish abaxially with age, stipe with a continuous or broken row of linear aerophores on each side, base with a mass of long (1-1.5 cm) hairs, upper part of stipe and rachis covered with small, appressed flaccid hairs becoming glabrescent; lamina 2-pinnate-pinnatifid, 1.5-3 m; medial pinnae 40-80 × 15-30 cm, lower pinnae shortened, deflexed; pinnae many, alternate, stalked, pinnules shortly stalked, usually of ± equal length on either side of rachilla; pinnule segments slightly falcate, apiculate, margins crenulate to serrulate-serrate; veins free, fertile ones simple, sterile simple or forked; lamina subleathery, adaxial surface deep green, abaxial surface glaucous, glabrous on both sides, except hairy on midrib; venation visible on both surfaces, free, lateral veins simple or forked. Sori usually 1-5 at base of lower pairs of pinnule segments; indusia bivalvate, outer indusia orbicular, inner ones ± oblong; outer valve of indusium usually large; paraphyses dark reddish brown. Spores pale yellowish, with equatorial flange.
Rhizome massive, prostrate, very densely covered with golden yellow hairs. Stipes thick, sometimes attaining to 2 cm diam., more than 1.5 m long in larger ones, densely covered with shining, golden yellow, long (more than 4 cm long in some larger ones), slender or warty hairs at base, the hairs on upper parts not so dense, brown to darker, setose, gradually becoming shorter upwards; lamina large, up to 2 m in length, more than 1 m in width, bipinnate; pinnae many, the largest ones up to 75 cm long, 25 cm wide, with numerous pinnules; pinnules deeply pinnatifid throughout, very shortly stalked or subsessile at posterior parts of pinnae, linear-lanceolate, gradually narrowing towards acuminate apex, broadly cuneate to subtruncate at base, 10–15 cm long, 1.5–2.5 cm wide; ultimate segments oblong, oblique to subfalcate, acute at apex, shallowly but distinctly dentate at margin, glaucous in lower surface, 0.8–1.4 cm long, about 3 mm broad, with intervals of 4 mm between the adjacent costules; costae and costules covered with pale, entangled, flaccid, appressed hairs below; veins distinct, once (or twice in larger lobes) forked, sparsely hairy below. Sori terminal on usually unbranched lower veins, parallel to edge of lobes, protected by two indusia; outer indusia round, inner ones elongate at maturity, oblong.
|ninla phosi (นิลโพสี)(Peninsular)||Thai||THA|
|pho si (โพสี)(Peninsular)||Thai||THA|
|kut sua (กูดเสือ)(Peninsular)||Thai||THA|
|wan kai noi (ว่านไก่น้อย)(Central)||Thai||THA|
|la-ong faifa (ละอองไฟฟ้า)(Central)||Thai||THA|
|khon kai noi (ขนไก่น้อย)(Northeastern)||Thai||THA|
|hut phipa (กูดผีป่า)(Northern)||Thai||THA|
|kut phan (กูดพาน)(Northern)||Thai||THA|