Acroptilon repens or Centaurea repens
(Russian Knapweed)
Family: Asteraceae (Sunflower)
Noxious Weed!
Russian Knapweed is a creeping perennial weed. Flowers are lavendar. Bracts below the flowers are papery. Russian Knapweed is a noxious weed that should be aggressively controlled. It is also toxic to horses.

Compare to Diffuse Knapweed. Diffuse Knapweed has stiff bracts with bristles on the margins.

Vegetation zone:  Plains, Foothills, Montane
Time of bloom:  June - September
Origin:  Introduced  Noxious Weed
Eastern Colorado Wildflowers