Page author: Don Knoke
Centaurea diffusa
diffuse knapweed, tumble knapweed, white knapweed
WTU specimens
Other herbaria

Distribution: Introduced throughout the Pacific Northwest; widespread and common in eastern Washington

Habitat: Noxious weed of dry, disturbed areas

Flowers: July - September

Origin: Introduced from the eastern Mediterranean region

Conservation Status: Not of concern

Description:
General:

Diffusely branched annual or biennial 1-6 dm. tall.

Leaves:

Leaves small, more or less pinnatifid, the lower ones early deciduous, the reduced ones or the inflorescence mostly entire.

Flowers:

Heads numerous, narrow; involucre 8-10 mm. high, the middle and outer bracts coarsely comb-like and tipped with a slender spine 1.5-4 mm. long; flowers few, white or rose-purple, the marginal ones not enlarged; pappus wanting; receptacle densely bristly.

Accepted Name:
Centaurea diffusa Lam.
Publication: Encycl. 1: 675. 1785. 1785.

Synonyms & Misapplications:
(none provided)
Additional Resources:

PNW Herbaria: Specimen records of Centaurea diffusa in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Centaurea diffusa checklist entry.

E-Flora BC: Centaurea diffusa atlas page.

CalPhotos: Centaurea diffusa photos.

USDA Plants: Centaurea diffusa information.

39 photographs:
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