Sp. Pl. 2: 649. 1753.
Annuals; glabrous or pubescent distal to base. Stems erect, branched distally, 1–4 dm. Basal leaves absent. Cauline leaves petiolate or (distal) sessile; blade spatulate or oblanceolate to oblong, 2–6 cm × 5–15 mm, margins pinnatifid or dentate, or (distalmost) entire or dentate. Racemes considerably elongated in fruit. Fruiting pedicels spreading to slightly descending, 3–10 mm. Flowers: sepals oblong, 1.5–3 mm; petals white or pink to purple, abaxial pair 5–8 × 2–5 mm, adaxial pair 2–5 × 1.5–3 mm. Fruits suborbicular to broadly ovate, 4–6(–7) × 3–6 mm, apically notched; valves extending into acute to obtuse wing; style 0.8–2 mm, exserted or included in apical notch. Seeds narrowly winged, 2–3 mm. 2n = 14.
Phenology: Flowering Jun–Aug.
Habitat: Escape from cultivation, waste places, old fields, lawns
Introduced; N.S., Ont., Mich., w Europe, introduced also in South America.