Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Disturbed areas of sagebrush desert, ponderosa pine forest openings, roadsides, fields, wastelots, and other disturbed areas.
Flowers: May-September
Origin: Introduced from Eurasia
Growth Duration: Annual, Biennial
Conservation Status: Not of concern
Annual herb, the erect, freely-branching stems 3-15 dm. tall, glabrous above and with a few stiff hairs below.
Leaves alternate, broadly lanceolate or oblong to oblanceolate, up to 1.5 dm. long, petiolate, the lower ones pinnatifid, the segments often pointing backward, becoming pinnatifid with linear segments above.
Inflorescence of bractless racemes; pedicles stout, spreading, 4-10 mm. long; sepals 4, somewhat spreading, 4 mm. long; petals 4, pale yellowish, clawed, 6-8 mm. long; stamens 6; style lacking, stigma 2-lobed.
Siliques linear, terete, 5-10 cm. long, slightly broader than the pedicles, spreading and rigid; valves with a prominent mid-nerve and 2 evident lateral nerves; seeds in 1 series.
PNW Herbaria: Specimen records of Sisymbrium altissimum in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Sisymbrium altissimum checklist entry.
E-Flora BC: Sisymbrium altissimum atlas page.
CalPhotos: Sisymbrium altissimum photos.
USDA Plants: Sisymbrium altissimum information.