Erect strigose annual up to c. 30 cm high, with few long and slender branches from the base. Leaves nearly exclusively cauline, sessile, linear-lanceolate, up to 3 cm by 1½ mm, herbaceous, entire, acute. Flowers solitary, axillary, on patent, up to 2 cm long, filiform pedicels; bracteoles 0. Calyx lobes lanceolate, 1½ by 0.3 mm, acute. Corolla 1 cm long, yellow, at base reddish, thinly villous, the lobes broadly winged. Capsules ellipsoid, 5 mm long. Seeds c. 10, ovate, 1½ by 1 mm, granulate, with a marginal rib.