Small perennial herbs with slender, creeping, rhizomes rooting in the mud. Leaves petioled and with 2-to 4 foliate blades or filiform and bladeless. Sori borne within hard round to bean-shaped sporocarps, which arise from the base of the petioles or near them and bear microspores, which produce antheridia and macrospores which produce female gametophytes. Three genera. (Munz, Flora So. Calif. 33).