Perennial herbs with a large, more or less erect, scaleless rhizome. Stipes bearing both a sterile and a fertile lamina. Sterile laminas pinnate, with broad pinnae. Fertile laminas pinnate, with the narrow pinnae covered with dense clusters of sporangia, the whole forming a tassel-like apex to the frond. Sporangia marginal or superficial, all alike and developing simultaneously, dehiscing by a slit. Indusia absent. Annulus consisting of a group of thick-walled cells near the apex. Spores numerous, green. Prothallus green, cordate, fleshy, surface-living.

Contains three genera and about 19 species, cosmopolitan.