Herbs, shrubs or climbers, rarely trees or dwarf succulents, usually with milky latex. Lvs usually opposite, less commonly verticillate, simple, exstipulate, sometimes reduced to scales. Fls in axillary or terminal cymes or cymose umbels, ☿, actinomorphic, 5-merous. Calyx deeply lobed; lobes imbricate or valvate. Corolla gamopetalous; lobes contorted or valvate in bud. Corona usually present, simple or of separate scales, in a single or double row. Anthers united in a ring and usually adnate to stigma, forming a gynostegium. Pollen usually aggregated in pollinia, sometimes in tetrads, attached to translators (organs for transferring pollen, usually arm-like processes). Disc 0. Ovary superior. Carpels 2, free below, united at the disc-like stigma. Fr. a pair of follicles, often only one developing. Seeds with apical coma of long silky hairs.