Rhizome, terete or dorsiventrally flattened, 2-6 mm thick, short-creeping, internodes 2-11 mm long, not white waxy, roots densely set; vascular strands 9-12, with sclerified sheaths, sclerenchyma strands 8-15. Rhizome scales pseudopeltate, sparsely set, appressed, ovate, narrowly ovate or triangular, 1.5-4 by 0.5-2 mm, margin denticulate to dentate, apex acute, clathrate or subclathrate, central region glabrous. Fronds not or slightly dimorphic, stipitate, thin-herbaceous. Sterile fronds: stipe 1.5-25 cm long, 2-4 mm thick; lamina simple, narrowly ovate to obovate or linear, 20-70 by 3.5-15 cm, index 4-8, base narrowly angustate, decurrent into a long wing, margin entire or sinuate, apex acuminate, lower surface without acicular hairs. Fertile fronds: stipe 0.5-45 cm long, lamina 20-50 cm long; otherwise similar to the sterile ones. Venation: veins prominent and distinct, 6-10 mm apart, more or less straight, dichotomously branched near the margin, connecting veins 6-10, catadromous, forming equally sized, sometimes irregularly shaped, areoles, sometimes also a row of small primary costal areoles; included veins more or less immersed and indistinct or prominent and distinct, variously anastomosing, free veinlets simple or once forked. Sori separate, round or elongate along veinlets, superficial or slightly immersed, 1 by 2-5 mm, mostly irregularly scattered on the smallest veinlets, 2 per veinlet, occasionally on tertiary veins, 10-30 per sq.cm, on the whole surface of the lamina, present in marginal areoles, generally present in costal areoles; paraphyses simple uniseriate hairs with glandular topcells, 2-or 3-celled.
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