Rhizome short creeping to suberect, variable in thickness 1-4 cm diam. including bases of old stipes, scaly at the apex but scales not usually persistent, scales narrowly elliptic-ovate, attenuate to acute, 0.3-1.4 by 0.1-0.4 cm, entire, dark reddish brown sometimes fading and slightly paler at the margins. Fronds both sterile and fertile fronds heteromorphic, dissected fronds 20-90 by 4-30 cm, fertile fronds often longer than sterile. Stipes 3-20 cm, up to half the length of the frond (stipes of fertile fronds usually longer than those of sterile fronds), variable in thickness, glabrous except for scales at the base similar to those of the rhizome, sometimes short pilose reddish brown hairs at base of stipe. Lamina narrowly elliptic, tapering evenly to both ends (simple fronds) to ovate or deltoid (lobed, pinnatifid or pinnatisect fronds), 2-13 pairs of pinnae then 0-11 pairs of well-spaced, very reduced vestigial pinnae or crescent shaped lobes extending down the rhachis of larger fronds, fertile lamina shows a similar range of variation from simple entire to pinnate. Rhachis and costae stramineous, brown, reddish brown, dark purple, or black depending on subspecies, glabrous. Sterile pinnae or lobes narrowly elliptic, ensiform, tending to falcate, attenuate at apices, constricted near rhachis, often widening at the base, varying greatly in size, 2.5-21 by 1.3-3.2 cm, adnate decurrent, coriaceous, margins with a fine cartilaginous border, entire, often appearing crenate towards their apices on dried specimens due to shrinkage of the very finely revolute margin between the terminal vein glands, veins immersed, inconspicuous but often more conspicuous on the lower surface, single or once furcate, terminating submarginally in a gland, basal segments reduced to progressively smaller and more distant crescent shaped lobes or wing-like auricles, terminal segment as large as or larger than lateral segments, asymmetrically pinnatifid at its base, subterminal segments with a markedly decrescent basiscopic wing extending down the rhachis. Fertile pinnae narrow linear, 4.5-25 by 0.3-0.5 cm, more distant on rhachis than sterile pinnae, adnate, markedly decurrent and almost contiguous in the upper portion of the lamina but towards the base usually more distant, reduced and sessile or sometimes shortly petiolate, sterile vestigial auricles down the rhachis, sori covering underside of pinnae except for sterile shortly attenuate apices up to 0.6 by 0.1 cm and in the more basal segments a short narrow sterile basal zone. Spores 45.3 by 33.9 µm (from 20 herbarium specimens), perine ridged, smooth, scabrous or microrugulose, exine smooth to scabrous or microverrucose.
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