[Wikipedia] Origins: Centaurea virgata is a species of Centaurea. It is native to Western Asia. The subspecies C. virgata subsp. squarrosa is known as squarrose knapweed. (contributed by Jessica Johnston)
[NPS] Introduction: Squarrose knapweed (Centaurea virgata ssp. squarrosa) is present in Utah, Nevada, California, Oregon, Wisconsin, and Michigan. How it was introduced to North America is unknown. (contributed by Jessica Johnston)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2023. Berkeley, California:The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 12/09/2023).