Annual to perennial herbs, rarely small shrubs. Leaves alternate, exstipulate.
Flowers usually hermaphrodite, actinomorphic, hypogynous.
Sepals 4, free, in 2 decussate pairs. Petals 4, rarely absent, free, clawed, imbricate or contorted, alternating with the sepals. Nectarial glands of various sizes, shapes, colours and dispositions around the base of the stamens and ovary. Stigma capitate to bilobed. Seeds in 1 or 2 rows in each loculus.