Annuals; glabrous or pubescent. Stems erect, branched distally, (1-)2-7(-8.5) dm, sparsely to densely (soft) pubescent at least basally, usually glabrous distally. Basal leaves rosulate; petiole (1-)2-5(-9) cm; blade broadly oblanceolate to oblong-oblanceolate (in outline), 3-8 (-10) cm × (10-)20-40(-60) mm, margins runcinate-pinnatipartite; lobes 2-5 on each side, oblong or lanceolate, much smaller than terminal lobe, margins subentire or dentate, (terminal lobe lanceolate, deltate, or often hastate). Cauline leaves similar to basal; (distalmost) blade with 1 or 2 lobes on each side, much smaller than terminal lobe, (terminal lobe narrowly lanceolate, linear, or hastate). Fruiting pedicels ascending to subdivaricate, stout, nearly as wide as fruit, 3-6 mm. Flowers: sepals ascending, oblong, 3.5-5.5 × 1-2 mm; petals spatulate, (6-)7-9(-10) × 2.5-4 mm, claw 3-5.5 mm; filaments (4-)5-8 mm; anthers oblong, 1-1.8 mm. Fruits narrowly linear, straight, smooth, stout, (5-)6-10 (-13) cm × 1-1.5 mm; valves glabrous or pubescent; ovules (60-)80-100(-140) per ovary; style (subclavate), 1-3(-4) mm; stigma prominently 2-lobed. Seeds 1-1.5 × 0.7-0.9 mm. 2n = 14.

Flowering Mar-early Jun. Waste grounds, roadsides, disturbed sites; 0-1300 m; introduced; B.C.; Ariz., Calif., Mass., Nev., Oreg., Tex., Wash.; Europe; sw Asia; n Africa; introduced also in Central America, South America, Australia.