Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to Nevada, east to the Atlantic Coast.
Habitat: Roadsides and drier disturbed areas.
Flowers: June-August
Origin: Introduced from Eurasia
Growth Duration: Annual, Biennial
Conservation Status: Not of concern
Pollination: Bees, flies, butterflies
Annual herb, the erect, freely-branching stems 4-12 dm. tall, glabrous above and with a few stiff, spreading hairs below.
Leaves alternate, broadly deltoid-lanceolate to lanceolate, short-petiolate, the lower ones up to 15 cm. long, pinnatifid with backward-pointing segments, the terminal lobe large, irregularly serrate, acuminate.
Inflorescence of bractless racemes up to 4 dm. long; pedicles slender, 7-20 mm. long, slightly ascending; sepals 4, lanceolate, 3.5 mm. long, somewhat spreading; petals 4, lemon yellow, clawed, 6-8 mm. long; stamens 6; style lacking, stigma 2-lobed.
Siliques linear, terete, 2-3.5 cm. long, ascending to erect; valves prominently 3-nerved; seeds in 1 series.
PNW Herbaria: Specimen records of Sisymbrium loeselii in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Sisymbrium loeselii checklist entry
OregonFlora: Sisymbrium loeselii information
E-Flora BC: Sisymbrium loeselii atlas page
CalPhotos: Sisymbrium loeselii photos