''Centaurea virgata'' is a species of ''
Centaurea''. It is native to
Western Asia. The
subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
''C. virgata'' subsp. ''squarrosa'' is known as squarrose knapweed.
It is found in northern California, Idaho, Utah and eastern Oregon. Plants are taprooted perennials and may reach a height of 36 inches. Flowers are formed in a slender urn-shaped head (4 to 8 flowers per head). Heads are slightly curved downward and resemble diffuse knapweed (Centaurea diffusa Lam.) on a diet but with rose-purple flowers. The head is made of a cluster of bracts and the tip of the bract is bent out. Seeds are pale brown and may disperse 60 feet when not spread by animals. The bent bract often allows the head to catch a ride on passing animals and is considered the mechanism for long distant dispersal. Older plants may have multiple rosettes on top of the long taproot. The taproot allows this weed to thrive in dry sites so it maybe more invasive than diffuse knapweed in ultra-dry rangeland.
virgata
Flora of Western Asia
{{Cynareae-stub