Distribution: Occurring in scattered locations on both sides of the Cascades crest; Yukon Territory to California, east across North America to the Atlantic Coast.
Habitat: Fields, roadsides, disturbed forest edge, wastelots, and other disturbed places.
Flowers: July-September
Origin: Introduced from central and eastern North America
Growth Duration: Annual, Biennial
Conservation Status: Not of concern
Pollination: Bees, flies, beetles, wasps
Annual or biennial, 3-25 dm. tall, usually glabrous and often glaucous, the juice milky.
Basal and lower cauline leaves 10-35 cm. long and 1.5-12 cm. wide, entire to pinnately lobed.
Heads numerous, 13-22 flowered, the flowers yellow, all ligulate; involucre 10-15 mm. high, cylindric but broadening at the base, the bracts imbricate; pappus bristles 5-7 mm. long, white.
Achenes blackish, very flat, with a median nerve on each face, 4.5-6.5 mm. long including the slender beak, which may be as long as the body.
PNW Herbaria: Specimen records of Lactuca canadensis in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Lactuca canadensis checklist entry
OregonFlora: Lactuca canadensis information
E-Flora BC: Lactuca canadensis atlas page
CalPhotos: Lactuca canadensis photos