• Premise of the study: Tribe Cardueae (thistles) forms one of the largest tribes in the family Compositae (2400 species), with representatives in almost every continent. The greatest species richness of Cardueae occurs in the Mediterranean region where it forms an important element of its flora. New fossil evidence and a nearly resolved phylogeny of Cardueae are used here to reconstruct the spatiotemporal evolution of this group.• Methods: We performed maximum parsimony and Bayesian phylogenetic inference based on nuclear ribosomal DNA and chloroplast DNA markers. Divergence times and ancestral area reconstructions for main lineages were estimated using penalized likelihood and dispersal–vicariance analyses, respectively, and integrated over the posterior distribution of the phylogeny from the Bayesian Markov chain Monte Carlo analysis to accommodate uncertainty in phylogenetic relationships.• Key results: The phylogeny shows that subtribe Cardopatiinae is sister to the remaining subtribes, and subtribes Carlininae and Echinopsinae appear as consecutive sister‐clades to the Carduinae/Centaureinae. Tribe Cardueae is inferred to have originated around the Mid Eocene in West Asia, which is also the ancestral area of most subtribes within Cardueae. Diversification within each subtribe began during the Oligocene‐Miocene period.• Conclusions: Most diversification events within Cardueae are related to the continuous cycles of area connection and division between the Anatolian microplate and the western Mediterranean Basin during the Oligocene‐Miocene and with the uplift of the Himalayan range from the Miocene onward. From these two regions, thistles dispersed and colonized the rest of the continents (e.g., the New World, Africa, and Australia), most likely during the colder Pliocene‐Pleistocene period.

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Taxonomic complexity has hindered the partitioning of the arti®cial genus Centaurea, even though it has long been recognized as a polyphyletic assemblage. On the basis of morphology, pollen type, karyology and DNA sequence analysis, previous workers have de®ned ®ve informal groups in the genus (Acrocentron, Centaurea sensu stricto, Cyanus, Jacea and Psephellus). However, the precise delimitation of these groups and their relationships remain largely unknown. Moreover, although some informal groups have been established among the rest of the subtribe (Amberboa, Carthamus and Stemmacantha), many genera cannot be classi®ed in any group. Newer molecular approaches are essential for resolving these problems. Sequences of the internal transcribed spacers (ITS) of nuclear ribosomal DNA and the chloroplast gene matK were analysed for a comprehensive sample of the whole subtribe, with the aim of clarifying the delimitation and the phylogeny of the groups of the Centaureinae. Results largely con®rm the suggested informal entities as natural groups, with some interesting changes of placement of some genera, especially in the Acrocentron and the Stemmacantha groups. Our results con®rm that the sections of Centaurea with Dealbata pollen type should be classi®ed as a dierent genus, Psephellus. In addition to morphology and suggested pollen type evolution, the ITS and matK phylogenies are also supported by karyological evidence. Our results con®rm that the natural delimitation of Centaurea that minimizes nomenclatural changes is possible only if a new type of the genus is designated.

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