Stems simple or branched distally, (1.5-)3-9(-13) dm; glabrous or pilose basally, trichomes to 1.5 mm. Basal leaves: petiole 3-16(-22) cm; blade reniform or cordate, (6-)15-88(-118) mm wide (shorter in length), surfaces glabrous or pilose. Cauline leaves: petiole shorter than basal; blade ovate, cordate, or deltate, to 15 × 15 cm, base cordate or truncate, margins acutely to obtusely toothed, apex acute. Racemes several-flowered. Fruiting pedicels terete, (2-)3-10(-15) mm. Flowers: sepals (2-)2.5-3.5(-4.5) × 0.7-1.5 mm; petals (2.5-)4-8 (-9) × (1.5-)2-3(-3.5) mm, base attenuate to clawlike; filaments 2-3.5(-4.5) mm; anthers oblong, 0.7-1 mm. Fruits divaricate-ascending, subtorulose, quadrangular or subterete, (2-)3-7(-8) cm × 1.2-2.5 mm; style (0.2-) 1-2(-3) mm. Seeds dark brown or black, narrowly oblong, 2-4.5 × 0.7-2 mm. 2n = 42. Flowering Apr-May. Roadsides, trails, railroad tracks, stream banks, waste places, fields, shaded woodlands, bluffs, thickets, steep slopes, disturbed fields, floodplains, woods, shaded forest floor; 0-1200 m; introduced; B.C., Ont.; Conn., Del., D.C., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., Tenn., Utah, Vt., Va., Wash., W.Va., Wis.; South America (Argentina); Eurasia; n Africa.