A large, glabrous, annual, up to 3 m tall (under cultivation). Leaves 3-5-costate, ovate-lanceolate or linear-lanceolate, 5.5-15 cm long, 1.5-8 cm broad, acute or acuminate, coarsely serrate, basal serratures backwardly prolonged into setaceous appendages; petiole up to 5 cm long; stipules linear, 6-10 mm long. Cyme 1 or 2-flowered, axillary or antiphyllous. Flowers yellow, 8-10 mm across, pedicellate; bracts linear-ovate, 2-3 mm long, 1.5-2 mm broad. Sepals linear oblong, 4-5 mm long. Petals obovate, 3-5 mm long, 2.5-3 mm broad, notched at the apex. Stamens 20-30, filaments c. 3 mm long. Carpels 5; ovary subglobose, 5-loculed, glabrous, truncate; style minute. Capsule subglobose-globose, 10-12 mm in diameter, beakless and depressed at apex, scabrous, ridged, tuberculate or muricate, 5-loculed, locules aseptate. Seeds cuneiform, c. 2 mm long, brown, glabrous.