Bachelor's Button, Garden Cornflower: Centaurea cyanus -
Diffuse Knapweed, Tumble Knapweed, White Knapweed: Centaurea diffusa (Synonym: Acosta diffusa) -
Hybrid Knapweed, Meadow Knapweed, Protean Knapweed: Centaurea X gerstlaueri (Synonyms: Centaurea debeauxii ssp. thuillieri, Centaurea ×moncktonii, Centaurea nigra× Centaurea jacea, Centaurea pratensis) -
Globe Knapweed: Centaurea macrocephala - Collected near Laurel (Conboy Lake NWR)
Short-fringed Knapweed, Tyrol Knapweed: Centaurea nigrescens (Synonyms: Centaurea dubia, Centaurea dubia ssp. nigrescens, Centaurea dubia ssp. vochinensis, Centaurea jacea ssp. nigrescens, Centaurea transalpina, Centaurea vochinensis) - Collected near Trout Lake, WA.
Spotted Knapweed: Centaurea stoebe (Synonyms: Centaurea biebersteinii (misapplied), Centaurea maculosa (misapplied), Centaurea paniculata ( misapplied), Centaurea stoebe ssp. micranthos) -