Centaurea crocata, described in 1984 from the Serra de Monchique in the Algarve (S Portugal), has a long history of confusion withC. prolongifrom S Spain. From the study of herbarium specimens and of living plants, authors conclude that all previous Portuguese citations ofC. prolongibelong actually toC. crocata. However, authors' studies confirm the real presence ofC. prolongiin some relictic localities in the limestones of the extreme south of the Algarve. A morphologic comparison between the two species is performed and authors suggest forC. crocataa hypothetical hybrid origin betweenC. prolongiand a species of sect.Chamaecyanus.