Plants often vinelike, small to medium-sized, terrestrial, epiphytic, or epipetric. Rhizomes short- to long-creeping. Stipes straw-colored, glabrous, jointed to short phyllopodia. Blades simple, pinnatifid, pinnate, has tate, or palmate, chartaceous or coriaceous. Veins prominent, anastomosing, forming irregular areoles with free, simple or branching, included veins. Sori small, exindusiate, round or slightly elongate, superficial, scattered irregularly over entire undersurface of blade or forming irregular rows between the veins.

The genus is distinguished by reticulate venation with areoles containing free, included, branched veinlets; and numerous small, irregularly distributed, naked sori, or sori arranged in irregular rows between veins.

Tropical or subtropical genus of about sixty diverse species concentrated in southeastern Asia but also from Africa, Australia, and the Pacific islands. Represented in Hawai 'i by a single endemic species with two varieties.