Rhizome rather short-creeping, 4-6 mm ø; scales dark castaneous, elongate-triangular, to 5 mm long, to c. 16-seriate at base, the uniseriate apex very short. Leaves close to more remote; petioles dark castaneous to blackish, dull, quadran-gular, upward sharply so and often sulcate, ± distinctly pale-angled, 10-50 cm long, shorter than the lamina. Lamina oblong, simply pinnate, 30-65 cm long, 15-25 cm wide, with 8-20 pinnae to a side and a conform terminal one; rachis similar to the petiole, sulcate, upward paler and narrowly marginate. Pinnae alternate or the lower ones opposite, ascending, coriaceous, olivaceous to fuscous when dry, subsessile or the lower ones with a short stalk-like base, linear, the largest 10-25 cm long, 7-10 mm wide, widest a little above the base, long-acuminate, unequally cuneate at the base; lower pinnae not rarely slightly reduced, the terminal pinna conform, with unequal base, occasionally with 1 or 2 reduced pinnae at its base. Margin of sterile pinnae serrate or biserrate, of fertile ones serrate, the teeth strongly ascending, broadly truncate, posteriorly rounded, each bearing a sorus; basal acroscopic tooth not rarely somewhat larger. Costa percurrent, abaxially elevated and rounded, stramineous. Veins often hidden, rather oblique, once forked or the anterior branch forked again, c. 1 mm apart, almost reaching the margin. Sori uni-or binerval (rarely trinerval), the upper ones most often binerval; indusium brownish, entire, semi-elliptic, 1/2-2, most often 2/3-1 mm long, c. 1/3 mm wide, very nearly equaling the margin, often strongly bulging at maturity. Spores brownish yellow, oblong, smooth, 30-35 by 24-26 μ.
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