Glabrous perennial herb; stems prostrate or decumbent, to c. 30 cm long, slender, generally 2-lined; rootstock ± woody. Lvs variable, sessile or occasionally short-petiolate, 4-14 × 0.5-6 mm, lanceolate or narrow-elliptic to suborbicular, with black, often scattered intramarginal glands; pellucid glands usually 0 below; base broad-cuneate or rounded; apex slightly emarginate, obtuse or mucronulate. Infl. terminal, few-flowered. Sepals very unequal, 2 broad and 3 narrow, 2-4-(5) mm long, broad-ellipsoid to narrow-oblong or elliptic, with black glands at margin or scattered over surface, entire or irregularly toothed in upper part, occasionally marginal glands stalked; apex obtuse or mucronulate. Corolla 5-12 mm diam., = or > calyx, yellow; petals lanceolate, oblanceolate or obovate, nearly always black glandular-ciliate, at least towards apex. Stamens in 3 bundles, < petals. Styles 3, < ovary. Capsule 6-10 mm long, ovoid, dry. Seeds c. 0.5 mm long, broadly short-cylindric, reticulate.