Page authors: Don Knoke, David Giblin
Cirsium undulatum
wavy leaf thistle

Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Michigan and Texas.

Habitat: Dry hillsides and plains at low elevations.

Flowers: May-September

Origin: Native

Growth Duration: Biennial, Perennial

Conservation Status: Not of concern


Stout, short-lived perennial from a tap-root, branched above and sometimes below the surface, 3-12 dm. tall, densely, closely, and persistently white-woolly throughout.


Leaves up to 3 dm. long, coarsely toothed to pinnatifid, the lobes ovate or deltoid, usually over 7mm. wide, the margins spiny.


Heads several to numerous at the ends of the branches; involucre 2.5-4 cm. high, its bracts with a glandular-glutinous dorsal ridge, the inner with pointed tips, the others with spine tips 3-5 mm. long; flowers all ligulate, pink-purple, but often so pale as to appear dirty-white.


Achenes 4-7 mm. long, light brown.

Accepted Name:
Cirsium undulatum (Nutt.) Spreng.
Publication: Syst. Veg. 3: 374. 1826.

Synonyms & Misapplications:
Cirsium undulatum (Nutt.) Spreng. var. undulatum
Additional Resources:

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

WA Flora Checklist: Cirsium undulatum checklist entry.

OregonFlora: Cirsium undulatum information.

E-Flora BC: Cirsium undulatum atlas page.

CalPhotos: Cirsium undulatum photos.

USDA Plants: Cirsium undulatum information.

42 photographs:
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