Annuals with erect, usually wiry branches rarely to 10 cm, little branched and rarely branched from the lowest 2 nodes, smooth. Leaves oblanceolate, rarely elliptic, 2.4–10 mm long, 0.8–3.5 mm wide, obtuse or rounded, rarely acute, flat or slightly convex above and somewhat convex below. Inflorescence 1 (rarely several) thyrses, each usually with 2 or 3 dichasia with lateral flowers of terminal cymes sessile or almost so when fruiting. Flowers 5(rarely 4)-merous; calyx-lobes triangular, 1.5–2.5 mm long, pointed, covered with papillae towards the apex; corolla white, more or less tinged red, lobes ovate, 1.2–2 mm long, acute, spreading; nectary scales usually T-shaped, 0.3–0.4 mm long, 0.6–0.7 mm wide, truncate to slightly rounded; carpels elongate-reniform, with 18–22 ovules. Follicles erect, smooth, releasing seeds through apical pore; fruiting pedicels rarely longer than 18 mm long; seeds 0.25–0.32 mm long, with longitudinal ridges with well-separated papillae. Flowers Aug.–Oct.