Annual herb 10–50 cm high. Stem unbranched or sometimes branched from the base, many-noded. Leaves as wide as or wider than long, ovate-orbicular to subreniform, 6–10 mm long, 5–13 mm wide, obtuse, shortly apiculate or distinctly acute, amplexicaul, cordate at the base. Inflorescences terminal, of few- to many-flowered dichotomous cymes; pedicels 2–5 mm long; bracts elliptic-lanceolate to broadly ovate, 5 mm long, 3 mm wide, acute, amplexicaul. Flowers 5-merous, yellow. Calyx lobes hyaline, lanceolate to ± elliptic-lanceolate, 3–4.5 mm long, 0.9–1 mm wide, acute; calyx wing wider ± above the middle, sometimes at the base. Corolla tube up to 4.8 mm long; lobes oblong-lanceolate, elliptic-ovate, 2.5–4.6 mm long, 1.5–2 mm wide, obtuse, conspicuously narrowed at the base. Filaments inserted in the sinuses of the corolla lobes; anthers 0.5–1 mm long, arced, with a minute ovoid to ellipsoid shortly stipitate apical gland, without basal glands. Ovary ellipsoid, 2.5–3 mm long, 1–1.5 mm diameter. Short-styled form: filament± 0.3 mm long; anthers up to 1 mm long; style 0.3–0.7 mm; stigma clavate, secondary stigma ± confluent to the primary stigma, by no means distinct. Long-styled form: filament 0.4–0.8 mm long; anthers 0.5–0.7 mm long; style 2.1–2.7 mm long, exceeding stamens, with or without distinct secondary swelling or stigma 0.4–0.5 mm from the base of the style, 0.3–0.5 mm long, 0.3–0.4 mm wide, usually as wide or wider than long; stigma globose to ± bilobed, capitate, 0.25 mm long, 0.4 mm wide. Capsule ellipsoid, 5.6–7.2(–8) mm long, 2–4 mm diameter. Seeds numerous, 0.3–0.5 mm long, surface with continuous wing-like outgrowths. Fig. 2 (p. 8).
