Prostrate annual or perennial herbs. Leaves opposite, entire, slightly succulent. Flowers hermaphrodite, axillary, glomerulate, subsessile. Calyx 5-lobed, membranous at margins, coloured inside, green autside. Stamens 5-15, free, inserted in the upper part of the calyx tube. Ovary superior, 2-celled, of 2 united carpels. Stigmas 2, free. Capsule 2-celled, dehiscent by a 2-valved operculum, 4-seeded.