Perennial, glabrous, succulent herb. Stem 30-120 cm high, branched, erect, stout. Leaves simple, opposite, succulent, spathulate-oblong or spathulate, crenate, crenate-serrate, obtuse, 8-17 x 2.5-8 cm, petiole 2-5 cm long. Inflorescence axillary corymbose or paniculate. Flowers erect, large, bisexual, 4-merous, pedicel 3-8 mm long. Calyx lobes united at base, triangular, glabrous, acute, 7-10 x 2-4 mm. Corolla glabrous, yellow, lobes ovate, acute, 5-21 x 4-7 mm. Filaments inserted at the middle of corolla. Carpels 4, styles smaller than ovary, ovules numerous per locule. Nectar scales linear, 3-4 x 0.2-0.3 mm. Follicles, 6-10 x 2-4 mm. Seeds oblong, with longitudinal striae, 0.5-1 x 0.1-0.2 mm.