Distribution: In scattered locations on both sides of the Cascades crest in Washington; Alaska to California, east across the northern half of the U.S. and Canada to the Atlantic Coast.
Habitat: Disturbed open areas and forest edges at low to middle elevations.
Origin: Introduced from Eurasia
Growth Duration: Annual
Conservation Status: Not of concern
Annuals; stems 0.6-4.5 dm, not branched or branched towards ends, dense pubescence towards base and glabrous towards ends, with simple trichomes 0.5-1.3 mm and stalked trichomes with 2-4 rays, 0.1-0.5 mm.
Basal leaves often form rosettes, petioles ciliate, blades oblong or oblanceolate, 1-3.5 cm long and 5-15 mm broad, margins dentate to finely toothed or occasionally nearly entire; varying amounts of pubescence above and beneath with cruciform trichomes and stalked trichomes with 2-3 rays; cauline leaves generally 4-12 but sometimes 15, sessile, ovate or oblong, margins as basal, pubescent above and beneath, trichomes above as basal leaves and beneath mostly simple trichomes combined with 2-3-rayed trichomes.
Inflorescence racemose, usually 18-60 flowered, ebracteate, significantly elongated in fruit; rachis rigid and straight, fully glabrous; pedicels spreading, straight, 2-7 times longer than fruit, glabrous; sepals 4, ovate, 0.9-1.6 mm long, scarcely pubescent with simple trichomes; petals 4, yellow, narrower towards base with deep notches, 1.7-2.2 mm long and 0.6-1 mm broad; anthers 0.1-0.2 mm, broadly ovate to slightly reniform.
Silicles 5-8 mm long and 1.5-2.5 mm broad, oblong to elliptic or occasionally narrower toward base, plane, somewhat flattened; valves glabrous or pubescent with simple trichomes; ovaries generally containing 36-60 ovules; seeds ovoid, 0.5-0.7 mm long and 0.3-0.4 mm broad.