Centaurea jacea, brown knapweed or brownray knapweed, is a species of herbaceous perennial plants in the genus Centaurea native to and open woodland throughout Europe. It grows to 10–80 centimetres (4–31 in) tall, and flowers mainly from June to September. In Britain and America, it is often found as a hybrid of black knapweed, Centaurea nigra. Unlike the black knapweed, the flower heads always look as if they are rayed, forming a more open star rather than a brush-like tuft. Centaurea ×moncktonii is a fertile hybrid between black knapweed and brown knapweed.