Herbs, annual, 15–60 cm, glabrous, sometimes glaucous. Stems erect or shortly decumbent at base, becoming erect, branched from near base. Leaves: usually only proximalmost opposite, sometimes to midstem, distal alternate, erect to ± spreading; stipular glands absent; blade of proximal leaves narrowly to broadly elliptic-oblanceolate, 10–15 × 1.5–2.5 mm, margins entire, not ciliate, apex subacute to acuminate; 1-nerved. Inflorescences slender thyrses. Pedicels 1–4 mm. Flowers: sepals persistent, linear-lanceolate to lanceolate, 3–5.3 mm, margins not scarious, inner ones conspicuously glandular-toothed, outer entire or very sparsely glandular-toothed, apex acute to acuminate; petals yellow, oblanceolate, 4–7 mm; stamens 3–5 mm; anthers 1–1.5 mm; staminodia absent; styles distinct, 1.5–3 mm; stigmas capitate. Capsules triangular-ovoid to broadly ovoid, 2.5–3.5 × 2.7–3.5 mm, apex obtuse, somewhat tardily dehiscing into 10, 1-seeded segments, segments persistent on plant, false septa incomplete, proximal margins ciliate. Seeds 2–2.5 × 1.1–1.3 mm. 2n = 26.