Unarmed annual or rhizomatous perennial herbs, sometimes subshrubs; hairs variable. Lvs alternate or opposite, simple, entire, toothed or sinuate, petiolate. Fls usually solitary, axillary. Calyx 5-toothed, campanulate, strongly accrescent. Corolla rotate or campanulate, usually yellow with an olive or bluish purple patch at base, 5-lobed or 5-toothed. Stamens 5; filaments attached near apex of corolla tube, exserted; anthers yellow or bluish violet. Stigma filiform or capitate. Fr. a globose berry, invested in the persistent, inflated calyx. Seeds numerous, lenticular, with patterned testa, of moderate size.