Description

Key Characters:

Growth Form: Prostrate, usually annual herbs.

Stems: Stems 1–2 dm long, profusely branched.

Roots: Taproots 2–10 cm long.

Leaves: Leaves simple. Alternate or subopposite. Blades cuneate to obovate, 10–25(–40) mm long, 5–15(–20) mm wide, upper ones occasionally involucrate around the flowers, succulent, tuft of hairs in the axil. Margins entire. Sessile, inconspicuous tuft of hairs ca. 1 mm long in the axil. Stipules 2, connate basally.

Flowers: Flowers 2–6(–30) in cymose clusters. Flowers bisexual (perfect), actinomorphic or rarely slightly irregular, sessile or subsessile. Calyx of 2 sepals; sepals imbricate, persistent, 3–4(–8) mm long, keeled. Corolla of (4)5, yellow, broadly obovate, 3–10 mm long, distinct or connate at base, imbricate. Stamens 7–10(–15); filaments usually puberulent; anthers dithecal, opening by longitudinal slits. Ovary partly inferior, 2–3(–9)-carpellate, soon becoming 1-celled; ovules numerous, placentation free-central; styles 2–9, (4)5–branched.

Fruit: Capsules membranous; ca. 4 mm long; circumscissile ⅓–½ from base. Seeds black; glossy; ca. 0.5–0.6 mm in diameter; the surface granulate; cells of the seed coat with fine tubercles.

Ploidy: 2n = 14; 18; 36; 45; 52; 54

Habitat: Low elevation; open; disturbed habitats; especially urban and agricultural areas.

Elevation Range: 0–915 m.