[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. (link added 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. (link added 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]. 2024. Berkeley, California:The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 11/21/2024).