Centaurea | Centaurea nigra | Centaurea scabiosa | Centaurea jacea | Centaurea maculosa | Mined leaf of ''Centaurea nigra | Leaf of ''Centaurea scabiosa | Centaurea montana | Centaurea iberica | Centaurea diffusa | Centaurea cineraria | A shoot of ''Centaurea nigra |
Introduced species of plants in the area are also a threat, including red brome (Bromus madritensis ssp. rubens), yellow starthistle (Centaurea solstitialis), and medusahead (Taeniatherum caput-medusae).