Rhizome or creeping, bearing fronds well-spaced or
close together, scales peltate at the base, usually small and dull in colour,
at least at the middle part distinctly clathrate, the lateral walls of the cells often raised.
Stipe jointed to the rhizome. Fronds simple and entire or in few species deeply
lobed. Texture thin, green in colour. Main lateral veins sometimes welldefined,
sometimes not, veins forming many aeroles with the included veinlets. Sori
usually small and scattered irregularly, on the veins.