Distribution: Alaska to Newfoundland, south to California and North Carolina.
Habitat: Moist places.
Flowers: July - August
Conservation Status: Not of concern
Robust annual or biennial, 6-20 dm. tall, the juice milky, glabrous except for some hairs on the mid-vein on the underside of the leaves.
Leaves pinnatifid or toothed, 10-40 cm long and 4-20 cm. wide, distributed evenly along the stem.
Heads numerous in a rather narrow, elongate inflorescence, 13-34 flowered; involucre 10-14 mm. high, cylindric but broadening at the base, the bracts imbricate; corollas all ligulate, bluish to white, the tube more than half as long as the ligule; pappus of light brown capillary bristles.
Achenes 4-5.5 mm. long, compressed and thin-edged, nearly beakless.