An erect or suberect, 30-60 cm tall, annual herb. Stem and branches glabrous. Leaves 3-4-costate, oblong-lanceolate or linear-lanceolate or somewhat elliptic-obovate, 1.5-9 cm long, 0.6-2.2 cm broad, glabrous except the sparsely hairy veins, crenate-serrate, basal serratures prolonged into filiform spreading appendages or not, acute; petiole 5-12 mm long, hairy; stipules setaceous, 2-3 mm long. Cyme 1-3(-4)-flowered, antiphyllous, short peduncled. Flowers yellow, c. 1 cm across, subsessile; bracts subulate, 3-4 mm long. Sepals linear-oblong, 4-5 mm long, c. 2 mm broad, apiculate. Petals oblong, 3-4 mm long, c. 2 mm broad, obtuse. Stamens 10-15, filaments 4-5 mm long. Carpels 3; ovary cylindric, sulcate, 3-loculed, hairy; style small, stigma sparsely papillate. Capsules 1-3 together, erect, cylindrical, 1.5-4 cm long, c. 2 mm in diameter, not ribbed, glabrous, terminated by 3 spreading bifid tips, 3-loculed, locules aseptate. Seeds angular, obliquely truncate at both ends, black.