Distribution: Chiefly east of the Cascades in Washington but also found in the western lowlands; widely distributed throughout central and western North America.
Habitat: Moist areas and irrigated land, but also on drier areas.
Origin: Introduced from Eurasia
Conservation Status: Not of concern
Glabrous perennial from well-developed rhizomes, the stems up to 2 m. tall.
Leaves alternate, entire to dentate, the basal with blades up to 30 cm. long and 6-8 cm. broad, with petioles sometimes as long; cauline leaves reduced, becoming sub-sessile and entire.
Inflorescence of numerous, bractless, much-compounded racemes; pedicles terete, much longer than the fruits; sepals 4, early-deciduous; petals 4, white, 1.5 mm. long; stamens 6; style almost lacking.
Silicles ovate-rotund, 2 mm. long, strongly obcompressed, with a few soft hairs, not at all notched, tipped by the stigma.