Perennial, erect or prostrate to decumbent herbs or shrubs. Leaves petiolate or sessile, elliptic, ovate-lanceolate, oblong-spathulate, entire, acute-acuminate or obtuse. Flowers mostly large, red, yellow, purple or white, showy and chasmogamous or small and cleistogamous, pedicellate or sessile, solitary axillary or in terminal or axillary cymes or panicles, rarely spicate; bracts inconspicuous, usually linear and small or absent; bracteoles 2 or absent. Calyx deeply 5-partite, lobes linear or lanceolate, ± equal. Corolla infundibuliform or salver-shaped, tube straight, incurved or ventricose, the limb spreading, subequally 5-lobed, lobes ovate, obtuse, contorted in bud. Stamens 4, didynamous, all fertile, the filaments inserted below throat and basally united in pairs, included or exserted; anthers dorsifixed, dithecous, thecae oblong, parallel, equal, basally muticous. Ovary bilocular, ovules 2-10 in each locule; style slender, stigma unequally 2-lobed. Capsule oblong-cylindrical or clavate-obovate or ellipsoid, usually 4-20-seeded. Seeds compressed and flat, ovate or orbicular, on acute, strong retinacula.
A genus of c. 250 species, distributed in tropical and temperate regions of both the hemispheres. Represented in Pakistan by 5 species, of which 3 are native