Caudex short, erect; stipe usually winged in its distal part (wing 2-8 mm wide on each side in the type), basal scales to 10 mm long, 1.5 mm wide at base, firm and dark with paler margins; lamina on young plants trilobed, on mature plants consisting of a trilobed apical part decurrent by a narrow wing along the rachis which may or may not join with a pair of pinnae, lobes of pinnae usually wider in sterile than in fertile fronds; pinnae to 20 cm long, to 8 cm wide (sterile) or 4 cm (fertile), entire, acuminate, lacking basiscopic lobes, a small scaly bud sometimes present at base of costae on lower surface; venation similar in sterile and fertile fronds, forming many areoles containing branched free veinlets, the cross-veins between main veins very regular; lower surface of costae and main veins bearing sparse very short hairs, upper surface densely covered with thicker hairs; sori in 2 rows between cross-veins (4-5 irregular rows between main veins) on veins which surround aréoles, some sori present also on rachis-wing; indusia reniform but when dried sometimes apparently peltate, bearing stiff hairs 0.3 mm long on their upper surface.
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