Ten knapweed and cornflower species: flower colours and involucral details. Exact Wikimedia Commons photographs. An editorial selection, not a scientific ranking. Original video contributions: CC BY-SA 4.0. Individual photographs retain the licences and credits listed in attribution; public-domain and CC0 photographs remain so. Photograph credits: 1. File:Centaurea_cyanus_flower_001.jpg; Orikrin1998; CC BY 3.0; https://creativecommons.org/licenses/by/3.0; https://commons.wikimedia.org/wiki/File%3ACentaurea_cyanus_flower_001.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 2. File:Centaurea_montana.jpg; User:Stemonitis; CC BY-SA 2.5; https://creativecommons.org/licenses/by-sa/2.5; https://commons.wikimedia.org/wiki/File%3ACentaurea_montana.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 3. File:Centaurea diffusa sl7.jpg; Stefan.lefnaer; CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0; https://commons.wikimedia.org/wiki/File%3ACentaurea_diffusa_sl7.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 4. File:IMG_1538-Centaurea_macrocephala.jpg; C T Johansson; CC BY 3.0; https://creativecommons.org/licenses/by/3.0; https://commons.wikimedia.org/wiki/File%3AIMG_1538-Centaurea_macrocephala.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 5. File:Centaurea_nigra-3233.jpg; Julie Anne Workman; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0; https://commons.wikimedia.org/wiki/File%3ACentaurea_nigra-3233.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 6. File:20130602Centaurea scabiosa1.jpg; AnRo0002; CC0; http://creativecommons.org/publicdomain/zero/1.0/deed.en; https://commons.wikimedia.org/wiki/File%3A20130602Centaurea_scabiosa1.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 7. File:Centaurea jacea 1.jpg; Franz Xaver; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0; https://commons.wikimedia.org/wiki/File%3ACentaurea_jacea_1.jpg; Cropped to upper 58 percent of original photograph to enlarge open head and bracts; scaled and fitted with title and caption bars. 8. File:Yellow_star_thistle.jpg; Peggy Greb; Public domain; https://commons.wikimedia.org/wiki/Help:Public_domain; https://commons.wikimedia.org/wiki/File%3AYellow_star_thistle.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 9. File:Centaurea_calcitrapa_001.jpg; Philmarin; CC BY-SA 3.0; https://creativecommons.org/licenses/by-sa/3.0; https://commons.wikimedia.org/wiki/File%3ACentaurea_calcitrapa_001.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence. 10. File:Centaurea_maculosa_Bozeman.jpg; Matt Lavin from Bozeman, Montana, USA; CC BY-SA 2.0; https://creativecommons.org/licenses/by-sa/2.0; https://commons.wikimedia.org/wiki/File%3ACentaurea_maculosa_Bozeman.jpg; Whole-image fit and scaling; title and caption bars added. Photograph licensed under the stated source licence.