Rhizome short-creeping, c. 2 mm ø; scales reddish brown, narrowly triangular, to 2 mm long, to c. 8-seriate at the sometimes rather suddenly broadened base, the apical 1/3 or 1/4 uniseriate. Leaves close; petioles stramineous, sharply quadrangular and shallowly sulcate, 10-30 cm long, about as long as the lamina. Lamina oblong, 15-30 cm long, bipinnate (in juvenile yet partly fertile plants simply pinnate), with 1-4 pinnae to a side and a conform terminal one. Primary rachis similar to the petiole. Pinnae 10-15 cm long, 9-16 mm wide, obliquely ascending, sub-opposite, sessile, widest in the lower half, gradually and strongly acuminate. Secondary rachises abaxially sharply bi-angular almost to the base, shallowly sulcate. Pinnules c. 25-40 to a side, close, subcontiguous, subsessile, ± ascending, especially the upper ones, herbaceous, dark green or olivaceous when dry, approximately semi-ovate in outline, the larger ones 7-8 by 2.5-3 mm, without a distinct outer margin, the lower margin usually convex, the upper margin with mostly 3 major incisions reaching down to the middle or a little less, the basal lobes often, the other ones occasionally again incised; lobes, especially the outer ones, often oblique, mostly 0.75-1 mm wide, approximately parallel-sided, truncate or faintly convex and slightly erose if fertile, narrowed-rounded if sterile, the wing joining the lobes c. 1 mm wide. Upper pinnules gradually and strongly reduced, confluent into the narrow pinna-apex. Veins immersed, evident, 2 or 3 in the larger lobes, single in the smaller ones. Sori usually bi-or trinerval (uni-to quadrinerval); indusium thin, pale, entire, 0.3-0.4 mm wide, not quite reaching the margin, ± reflexed at maturity. Spores pale yellowish, trilete, smooth, c. 22 μ.
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