Perennials; (terrestrial or of wet habitat, not submerged, rhizomes thickened, short); usually gla-brous, rarely pubescent proximally. Stems (simple from base), erect, much-branched distally, 4-11(-18) dm. Basal leaves not rosulate; blade margins pinnatifid. Cauline leaves sessile; blade lanceolate, (2.5-)4-12(-15) cm × 5-20(-25) mm, base auriculate to amplexicaul, margins entire or serrate. Racemes elongated. Fruiting pedicels divaricate-ascending to horizontal, straight, 4-15 mm. Flowers: sepals ascending, oblong, 2-3 × 1-1.3 mm; petals yellow, obovate, 3-5 × 1.7-2.5 mm; median filaments 2.3-3 mm; anthers ovate, 0.4-0.6 mm. Fruits silicles (rarely produced), straight, globose or subglobose, 2.5-3.2 × 1.5-2.7 mm; ovules 18-40 per ovary; style 1-1.5(-2) mm. Seeds biseriate, reddish brown, ovoid, 0.7-0.9 mm, finely colliculate. 2n = 16. Flowering May-Jul. Mud flats, floodplains, fields, roadsides, lakeshores, marshes, ditches, stream banks, wet grasslands, waste grounds; 100-1900 m; introduced; Alta., Man., Sask.; Calif., Conn., Idaho, Ill., Iowa, Nebr., Nev., N.J., N.Mex., N.Y., N.Dak., Pa., Utah, Wash., Wis.; Europe.