Perennial herbs with opposite leaves. Flowers in axillary cymes, showy and surrounded by an involucre of 5 bracts. Perianth infundibuliform, constricted above the ovary; limb 5-lobed, deciduous. Stamens 5-6, exserted. Style 1, stigma capitate. Anthocarp coriaceous, ribbed. Nut ribbed.