Annual herbs or perennial subshrubs, glabrous or almost so; branches fleshy. Leaves opposite, simple and bifid or paripinnate with 2 leaflets (rarely, and not in Victoria, more than 2), fleshy, sessile or petiolate; stipules present. Flowers bisexual, axillary, solitary, usually pedicellate; sepals 4 or 5, imbricate, with a green centre and membranous margins; petals (3–)4–5(–6), imbricate, clawed, white, yellow or orange, rarely red; stamens 4, 6 (not in Victoria), 8 or 10, anthers dorsifixed; disc between stamens and ovary sinuate or distinctly 3–5-lobed or 3–5-partite, the lobes at base of septa that separate the cells of ovary; ovary 3–5-celled, 3–5-angled, style subulate, stigma capitate or lobed. Fruit a 4- or 5-angled loculicidal capsule or an indehiscent capsule with 3 or 4 longitudinal wings or breaking into 2–4 dorsally winged mericarps; seeds 1–6 per cell, with endosperm, often mucilaginous when wet.
About 120 species, from the Mediterranean to central Asia, South Africa and Australia; c. 30 species in Australia.