These invasive plants include the diffuse knapweed ("Centaurea diffusa") and reed canary grass ("Phalaris arundinacea"). Centaurea scabiosa or greater knapweed is a perennial plant of the genus "Centaurea". In the Asteraceae, the knapweed "Centaurea diffusa" forms tumbleweeds. The squarrose knapweed is an herbaceous perennial plant. Invasive plants include the diffuse knapweed and reed canary grass. The wildflower meadow includes ox-eye daisies, yellow rattle and knapweed. Spotted knapweed primarily affects rangelands of the northwest United States and Canada. Spotted knapweed likely spread to North America in an alfalfa shipment. Greater knapweed is found growing in dry grasslands, hedgerows and cliffs on lime-rich soil. Other examples are "Centaurea solstitialis" (yellow starthistle) and "Centaurea diffusa" (diffuse knapweed). The plant is a thorny winter annual species in the knapweed genus. Both the female and male feed primary on bramble blossom and common knapweed. Brown knapweed ("Centaurea jacea") is different in having pale brown bract appendages, no pappus. Centaurea maculosa, the spotted knapweed, is a species of "Centaurea" native to eastern Europe. Various colour-forms of greater knapweed may be found as well as common twayblade.