Foetid annual herb to c. 1 m tall, puberulent, especially when young. Stems usually green or rarely purple. Petiole to c. 7 cm long. Lamina 5-30-(40) × 3-20-(25) cm, narrow- to broad-ovate, lobed; veins remaining puberulent, otherwise lamina becoming glabrous; apex of lobes acute or short-acuminate. Calyx 4-5 cm long, ribbed, reflexing at fruiting; teeth 5-8 mm long, unequal. Corolla 6-8-(9.5) cm long (excluding lobes), usually white or rarely light purple, funnelform; lobes 4-8 mm long, aristate. Fr. 3-5 × 2-3 cm (excluding spines), ovoid, erect, largest towards base of cyme; spines numerous, to 1 cm long, slender, the largest concentrated in upper 1/2. Seeds 2-3 mm wide, reniform, eventually black, irregularly rugose.