About Centaurea jacea L.
Centaurea jacea, commonly known as brown knapweed or brownray knapweed, is a species of herbaceous perennial plant in the genus Centaurea. It is native to dry meadows and open woodland across Europe, with its native range extending to West Siberia and the Caucasus. In Britain and America, it is often found as a hybrid with black knapweed, Centaurea nigra. Unlike black knapweed, the flower heads of Centaurea jacea always appear rayed, forming a more open star shape instead of a brush-like tuft. Brown knapweed has been introduced to North America, where it is often considered an invasive species, especially in the northeastern United States and Canada.
