Distribution: Introduced noxious weed, found across the United States and Canada.
Habitat: Usually in disturbed ground, dry to wet.
Flowers: July - October
Origin: Introduced from Europe
Conservation Status: Not of concern
Perennial with long vertical roots and creeping horizontal roots, glabrous below the inflorescence, 4-20 cm. tall.
Leaves prickly margined, the lower and middle ones pinnately lobed or pinnatifid, 6-40 cm. long and 2-15 cm. wide, becoming less lobed, smaller and widely spaced upward.
Heads several in an open, somewhat flat-topped inflorescence, 3-5 cm. wide in flower; fruiting involucre 15-22 mm. high; involucres and peduncles covered with glad-tipped hairs in one variety, glabrous in the other.
Achenes 2.5-3.5 mm. long, with 5 or more prominent ridges on each face.
This is the only perennial species of Sonchus found here, and it is generally a larger plant with much larger flowering heads than the annual species.