Shrubs or small trees of maritime habitats with pneumatophores, and terete branchlets conspicuously swollen at nodes. Leaves simple, opposite, lanceolate, oblong-lanceolate or elliptic, decussate, coriaceous, entire, exstipulate. Inflorescence terminal or axillary, often capitate cymes. Flowers regular, hermaphrodite, sessile, yellow or yellowish. Calyx deeply 5-lobed with imbricate, ovate lobes subtended by a false involucre of a scale-like bract and 2 alternate scale-like bracteoles (prophylls). Corolla gamopetalous, short, cylindrical, campanulate-rotate, actinomorphic or subequal, deeply 4-lobed. Stamens 4, inserted in throat of the corolla tube, equal or somewhat didynamous. Ovary superior with 2 united carpels and free central placentation; style shortly divided; ovules 4, pendulous. Fruit a capsule, broadly ellipsoid, compressed, dehiscent by 2(—4) thick valves; seed usually only one, erect; embryo with 2 large, longitudinally folded cotyledons and villous radicle, viviparous; endosperm fleshy.