Herbs or subshrubs, sometimes robust, 0.5-1.5 m tall, glabrescent. Petiole 3-5.5 cm; leaf blade broadly ovate, 8-17 × 4-14 cm, membranous, glabrescent, base asymmetric, cuneate, irregularly sinuous or dentate-lobed, apex acuminate, veins 3-5 pairs. Flowers erect. Pedicel 5-12 mm. Calyx tubular, 5-angular, 3-5 cm. Corolla white or pale purple, greenish at base, sometimes purple distally, funnelform; limb 3-5 cm in diam.; lobes 6-10 cm, mucronate at apex. Filaments ca. 3 cm; anthers 3-4 mm. Capsules erect, globose or ovoid, 3-4.5 × 2-4 cm, with copious prickles, rarely smooth, dehiscent by 4 equal valves, subtended by remnants of persistent calyx. Seeds black, ovate or discoid, ca. 4 mm in diam. Fl. Jun-Oct, fr. Jul-Nov.