Plants annual or winter annual, from slender taproot. Stems decumbent proximally, ascending distally, diffusely branched, 4-angled, to 80 cm, with single line of hairs along each internode. Leaves petiolate (proximal and those on sterile shoots) or sessile (distal and mid stem); blade ovate to broadly elliptic, 0.5-4 cm × 2-18 mm, base round to cuneate, margins entire with few cilia at base, thin, apex acute to short-acuminate, ± glabrous. Inflorescences terminal, 9-many-flowered cymes; bracts ovate to lanceolate, 3-25 mm, reduced distally, herbaceous, sparsely ciliate on margins and underside. Pedicels erect, often becoming deflexed, 5-40 mm, pubescence a single line of hairs. Flowers 5-7 mm diam.; sepals 5, veins obscure, lanceolate, 5-6.5 mm, margins narrow, membranous, apex acute, pubescent; petals 5 (rarely absent), 2-5 mm, shorter than or equaling sepals; stamens 8-10; styles 3, ascending, outwardly curved, 0.5-1 mm. Capsules green to straw colored, ovoid-oblong, 5-7 mm, ca. equaling sepals, apex obtuse, opening by 6 slightly recurved valves; caropohore absent. Seeds very dark brown when mature, round, 1.1-1.7 mm diam., tuberculate; tubercles conic, taller than broad, apex acute. 2n = 22.