An erect, subglabrous, annual or biennial, up to 3 m tall (in cultivation). Stem basally woody, branched. Leaves 3-5-costate, lanceolate to ovate-lanceolate, 2.2-9 cm long, 1.8-4.2 cm broad, glabrous except the scattered hairy veins, serrate, basal serratures prolonged into filiform deflexed appendages, acute or acuminate; petiole 1-3.2 cm long, hairy; stipules subulate, 8-12 mm long. Cyme 1 or 2-flowered, antiphyllous, shortly pedunculate. Flowers yellow, 12-15 mm across; subsessile; bracts subulate, 4-5 mm long. Sepals linear-oblong, 5-7 mm long, 1.5-3 mm broad, keeled, caudate, somewhat bullate outside. Petals oblanceolate, 7-8 mm long, 2.5-4 mm broad, hairy at the base, obtuse. Stamens numerous, somewhat united at the base, filaments 6-7 mm long; anthers subglobose. Carpels 5; ovary cylindric, subsulcate, 5-loculed, thinly hairy; style short, stigma 5-lobed, minutely papillate. Capsules 1 or 2 together, 2-7.2 cm long, with 4-5 mm long, entire beak, c. 4-5 mm across, 10-angled, glabrous, 5-loculed, locules transversely septate. Seeds greenish-black, triangular, ovate, c. 2 mm long.