Description from Flora of China
Shrubs or annual or perennial herbs; pubescence of simple hairs. Stems branched. Leaves solitary or paired, petiolate; leaf blade simple, entire or sinuate. Inflorescences solitary or few-flowered clusters at branch forks or leaf axils; peduncle absent. Flowers nodding or erect, actinomorphic. Pedicel erect or nodding. Calyx broadly campanulate to cup-shaped, denticulate, sometimes slightly enlarged. Corolla white, blue, or violet, campanulate or rotate, divided halfway or more. Stamens inserted near distal end of corolla tube; filaments slender; anthers yellow or purplish, ovoid, dehiscing longitudinally. Ovary 2- (or 3)- locular; ovules numerous. Style slender; stigma small, capitate. Fruit a moist berry, sometimes large, erect, nodding, or reflexed. Seeds yellowish, discoid; embryo coiled, subperipheral.
About 25 species: all in South America, two or three cultivated and naturalized worldwide; one species in China.