Somewhat foetid annual herb to c. 1 m tall, ± puberulent, at least when young. Stems light green. Petiole to 8 cm long. Lamina 5-18-(25) × 4-16-(20) cm, broadly ovate, shallowly lobed; veins somewhat puberulent, especially above; apex of lobes obtuse or subacute. Calyx 2.5-3.5 cm long, ribbed, reflexing at fruiting; teeth 3-5 mm long, subequal. Corolla c. 5 cm long, funnelform, white; lobes 1-2 mm long, aristate. Fr. to 5-(6) × 3-(4) cm (excluding spines), narrowly elliptic-ovoid, erect; spines moderate in number, to 2.5-(3) cm long, stout, the uppermost > lower. Seed c. 4 mm wide, subreniform, black, rugose.