Stems creeping or ascending, frequently branched. Leaves ± arching, 1--3 m × 12--50 cm. Rachis rounded abaxially, decidedly grooved adaxially. Pinnae 24--30(--40), usually not overlapping, 10--34 × 1.3--7 cm; proximal pinnae always distant, frequently rounded at tip; costal areoles 3 or more times longer than wide; distal 6--12 pinnae of fertile leaves bearing sporangia. Sporangia spread over abaxial surface of distal pinnae in fertile leaves; paraphyses stalked, ending with single isodiametric, irregularly lobed cell. Spores (37--)57(--72) µm diam., surface minutely tuberculate. 2 n = 60.