Members of the genus are annuals or perennials generally characterized by fleshy, opposite, unequal, smooth-margined leaves, a prostrate growth form, flowers with five perianth segments subtended by a pair of bracts, and a fruit with a winged lid.

The genus contains about 30 described species growing in tropical and subtropical regions, especially Australia.

One common species, Trianthema portulacastrum, desert horse purslane, is frequent as a weed in agricultural areas and is widely distributed.

[2] The genus Trianthema was first formally described in 1753 by Carl Linnaeus in Species Plantarum.

[1][3] The following is a list of species of Trianthema according to Plants of the World Online as at October 2020:[1] Media related to Trianthema at Wikimedia Commons