Annual, biennial or perennial herbs or less often shrublets or trees, usually with coarse hairs that arise from a tuberculate base; hairs appressed, subappressed or setose. Leaves alternate, simple, exatipulate. Inflorescence initially a scorpiod or helicoid cynic that uncoils at anthesis, sometimes spicate, loosely cymose or with solitary flowers. Flowers generally regular and bisexual or less often irregular, sometimes heterostylous. Calyx 5-lobed, often enlarging in fruit. Corolla 5 -lobed, salverform, funnelform or campanulate. Throat glabrous or with scales (appendages) or a zone of hairs, a nectiferous ring or collar sometimes present at base of corolla tube. Stamens 5, epipetalous, alternating with the corolla lobes, equal or unequal. Filaments exserted beyond the corolla tube or not. Ovary superior, 4-locular at maturity. Style gynobasic or terminal, usually simple; stigma entire or by splitting of style, 24-lobed. Fruit of 2 or 4 nutlets or drupaceous. Nutlets borne on a gynobase that is flat or raised and fused to the style base, keeled or not, attachment scar (areole) narrow or not; often differentiated into a disc and margin; margin smooth of appendiculate; surface smooth to hairy or variously ornamented.