Vascular Plants - Asteraceae - Acroptilon:
Acroptilon repens
Page Authors: Don Knoke, David Giblin
hardheads, Russian knapweed, Turkestan thistle 
Blooms: June-September
Habit: herb
Duration: perennial
Origin: Introduced
Distribution: Introduced chiefly east of the Cascades in Washington; widely distributed throughout much of North America.
Habitat: Dry, open areas at low elevation and foothills.
Species Description:

General: Coarse, bushy perennial from deep rhizomes, 4-8 dm. tall, finely loose white-woolly throughout.
Leaves: Lower cauline leaves up to 15 cm. long by 4 cm. wide, often few lobed; other leaves numerous, smaller, entire or with a few teeth.
Flowers: Heads numerous, terminating the branches; involucre pale yellow-green, 9-15 mm. high, the middle and outer bracts broad, glabrous, with rounded hyaline tips, the inner bracts narrower and tapering, with hairy tips; flowers purple; pappus bristles 11 mm. long; receptacle densely bristly.
Fruits: Achene
Accepted Name:
Acroptilon repens (L.) DC.
Synonyms:
Centaurea repens L.

Treated in Flora of the PNW as:
Centaurea repens
Additional Resources:

PNW Herbaria Specimens: View list of Acroptilon repens specimens in the Consortium of Pacific Northwest Herbaria database.

WTU Herbarium Specimens: View list of Acroptilon repens specimens in the WTU Herbarium database.

Washington Flora Checklist: Acroptilon repens treatment.

E-Flora BC: Acroptilon repens atlas page.

CalPhotos: Acroptilon repens images.

USDA Plants Database: Acroptilon repens.
Additional photographs of Acroptilon repens:
(click on a thumbnail to view larger photo)

Richard Old

Richard Old

Richard Old

Richard Old

Sue Winterowd, 2003

Sue Winterowd, 2005

Sue Winterowd, 2005
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Washington Native Plant Society
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