Annual herb, prostrate or erect to 23 cm high, glabrous or squamulose. Stem foliose throughout. Leaves ovate, elliptic or rarely linear, 2–12 mm long, 0.5–9 mm wide. Flowers terminal and axillary, solitary and in simple and compound umbellate clusters; pedicels to 20 mm long. Calyx campanulate, squamulose, 4-angled; tube 1–1.2 mm long; lobes c. 0.5 mm long, acuminate, often recurved at apices. Corolla white; tube 2–3 mm long; lobes 0.6–3 mm long. Stamens 0.8–1 mm long; anthers obtuse; dehiscence latrorse. Capsule obovoid or globular, c. 2 mm long, with upper part and horns squamulose-papillose; upper part of horns often joined by a membrane; fruiting style 0.5–1 mm long.