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Annuals. Stems unbranched or branched distally, (0.8-)2-8 (-10) dm, densely to moderately hirsute basally, trichomes simple, to 2.5 mm, often mixed branched ones, (glabrescent distally). Basal leaves withered by anthesis. Cauline leaves: blade lanceolate, narrowly oblong, or linear-lanceolate, (0.8-)1.5-5.5(-7) cm × 1-10(-20) mm, base sagittate or minutely auriculate, margins entire or, rarely, remotely denticulate, (often subciliate), apex acute, surfaces pubescent, trichomes primarily simple. Fruiting pedicels ascending, 4-14(-17) mm. Flowers: sepals 2-3.5 × 0.5-1 mm; petals pale yellow, (2.5-) 3-4(-6) × 1-2 mm; filaments 1.5-3 mm; anthers ca. 0.5 mm. Fruits pyriform to narrowly so, 3.5-5(-7) × 2-4(-5) mm, apex acute; valves each often with obscure midvein, margin narrowly winged; style 1-3.5 mm. Seeds reddish brown or brown, 0.8-1.4(-1.5) × 0.5-0.6 mm. 2n = 40.
Erect, 3–7 dm, rough-hairy; lvs entire or remotely denticulate; frs erect, 2.5–5 mm, obscurely rugulose, on pedicels 4–9 mm; seeds ca 1 mm; 2n=40. Fields and waste places, usually in sandy soil; native of the Old World, established as a casual weed throughout most of the U.S. and s. Can. Apr.–June.
