Description from Flora of China
Herbs annual or perennial, rarely subshrubs, pubescent or strigose, rarely scabrous. Leaves alternate, less often opposite, sessile or petiolate. Cymes terminal, rarely axillary, unilateral, scorpioid, bracteate or not. Calyx 5-parted. Corolla white or light bluish purple, less often yellow, cylindric or funnelform, strigose outside, glabrous and rarely appressed pubescent inside; throat frequently pubescent; limb 5-parted; lobes orbicular, sometimes linear, margin with folds or undulate. Filaments extremely short; anthers included. Ovary completely or incompletely divided into 4 lobes; ovules 4. Style terminal; stigma conical or ringlike. Fruit nutletlike dry drupes, without evident mesocarp at maturity, endocarp bony, dividing into 4 1-seeded or 2 2-seeded mericarps. Seeds straight or curved, usually with a thin endosperm.
About 250 species: tropical and temperate regions; ten species in China.
Heliotropium ovalifolium Forsskål var. depressum (Chamisso) Merrill is not included here because no material was available for study.