Succulent annual herbs, with conspicuous papillose epidermal cells; stems decumbent to ascending, internodes long. Leaves opposite, ± spathulate, entire (Australian plants). Flowers solitary, terminal and axillary, pedicellate; sepals 5, united, unequal, 2 smaller with membranous margins; petaloid staminodes many, yellow or white, flattened; stamens 5–10, filaments flattened, shorter than staminodes; styles 5; ovary inferior, 5-locular; ovules numerous, parietal. Fruit a 5-locular capsule, opening when wet; valves winged; seeds numerous, triangular to quadrangular.
3 species native to South Africa, 1 naturalised in Australia.