Common Centaury, European Centaurium: Centaurium erythraea (Synonym: Centaurium umbellatum) - Flowers commonly with 5 corolla lobes, the corollas often pink in color.
Desert Centaury, Tall Centaury, Western Centaury: Zeltnera exaltata (Synonym: Centaurium exaltatum) - Flowers commonly with 4 corolla lobes, the corollas often creamy in color.