Low annual herbs, with filiform stems and fibrous roots. Leaves basal or reduced to cauline scales or bracts. Flowers regular, perfect, the perianth with 6 small thick lobes, its tube adnate to the ovary. Stamens 3 or 6, included, inserted on the tube of the perianth; anthers 2-celled, the sacs transversely dehiscent. Style slender; stigmas 3, dilated; ovary inferior, with 3 central or parietal placentae. Ovules numerous. Capsule many-seeded. Seeds minute, oblong; endosperm none.

Ten genera and about 70 species, widely distributed in tropical regions. The family is represented in North America by the following genus and by Apteria of the Gulf States.

* Text contributed to the first edition by the late Rev. Thomas.Morong.