Page authors: Don Knoke, David Giblin
Cirsium arvense
Canada thistle, Canadian thistle, creepiing thistle
WTU specimens
Other herbaria

Distribution: Widely distributed throughout Washington; widely distributed throughout North America.

Habitat: Noxious weed that thrives in a variety of habitats.

Flowers: June-October

Origin: Introduced from Eurasia

Conservation Status: Not of concern

Description:
General:

Dioecious, mostly glabrous perennial from deep rhizomes, 3-15 dm. tall.

Leaves:

Leaves lanceolate or oblong, up to 2 dm. long, reduced upward, pinnatifid or occasionally merely lobed or toothed, weakly spiny.

Flowers:

Heads several; involucres 1-2 cm. high, the outer bracts tipped with weak, short spines; pappus of the pistillate heads longer than the corollas, that of the staminate heads shorter than the corollas; flowers pink-purple or occasionally white.

Fruits:

Achenes glabrous, about 4 mm. long.

Accepted Name:
Cirsium arvense (L.) Scop.
Publication: Fl. Carniol. ed. 2. 2: 126. 1772. 1772.

Synonyms & Misapplications:
Cirsium arvense (L.) Scop. var. arvense [HC]
Cirsium arvense (L.) Scop. var. horridum Wimm. & Grab. [HC]
Cirsium arvense (L.) Scop. var. mite Wimm. & Grab.
Additional Resources:

PNW Herbaria: Specimen records of Cirsium arvense in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Cirsium arvense checklist entry.

E-Flora BC: Cirsium arvense atlas page.

CalPhotos: Cirsium arvense photos.

USDA Plants: Cirsium arvense information.

43 photographs:
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