Shrubs or subshrubs, sometimes annual herbs, often with volatile oils; indumentum of stellate and glandular hairs. Lvs usually opposite, rarely alternate, simple; stipules present or 0. Fls solitary or in cymes, ☿, regular, actinomorphic, often large. Sepals 3-5, the outer 2 often < inner 3; inner sepals usually persistent. Petals usually 5, less often 3 or 0, caducous, crumpled in bud. Stamens numerous; filaments free. Ovary superior, sessile, 1-locular, or incompletely septate with 3-5-(10) parietal placentae. Style simple or 0; stigmas 1 or 3, free or united; ovules numerous. Fr. a many-seeded loculicidal capsule. Seeds numerous, with ± curved embryo, endospermic.