Taxonomic complexity has hindered the partitioning of the artificial genus Centaurea , even though it has long been recognized as a polyphyletic ass

The new outline of relationships in basal branches of the family Compositae Giseke confirms that the sister group to the tribe Cardueae Cass. are not Mutisieae Cass., but rather a group of African genera now classified as the tribe Tarchonantheae Kostel. This change implies that the monophyly of the Cardueae must be reassessed on a molecular basis. Moreover, new collections in recent years allow us to extend our sampling to 70 of the 74 genera of the tribe. We performed a new molecular study of the tribe using one nuclear region (ITS) and two chloroplastic markers (trnL-trnF and matK) in addition to a more appropriate outgroup. Our results confirm that the Cardueae is a natural group but indicate some changes in subtribal delineation: the subtribe Cardopatiinae Less. is recognized and some genera are moved to other subtribes (Myopordon Boiss., Nikitinia Iljin, Syreitschikovia Pavlov, and the Xeranthemum L. group). A recapitulation of a number of interesting questions that remain unresolved in the... Resumen El nuevo esquema de las relaciones en las ramas basales de la familia Compositae Giseke ha confirmado que el grupo hermano de la tribu Cardueae Cass. no es la tribu Mutisieae Cass., sino más bien un grupo de géneros africanos que ahora se clasifican como tribu Tarchonantheae Kostel. Este cambio implica que la monofilia de las Cardueae establecida sobre bases moleculares debe confirmarse. Además, nuestras nuevas recolecciones en los últimos años hacen que nuestro muestreo se extienda a 70 de los 74 géneros de la tribu. Hemos llevado a cabo un nuevo estudio molecular de la tribu usando una región nuclear (ITS) y dos cloroplásticas, además de seleccionar un grupo externo más adecuado. Nuestros resultados confirman que las Cardueae son un grupo natural, pero aconsejan algunos cambios en la delimitación subtribal: el reconocimiento de la subtribu Cardopatiinae Less. y el cambio de algunos géneros a otras subtribus (Myopordon Boiss., Nikitinia Iljin, Syreitschikovia Pavlov y el grupo Xeranthemum L.). Pr...

• Background and Aims The genus Centaurea has traditionally been considered to be a complicated taxon. No attempt at phylogenetic reconstruction has been made since recent revisions in circumscription, and previous reconstructions did not include a good representation of species. A new molecular survey is thus needed. • Methods Phylogenetic analyses were conducted using sequences of the internal transcribed spacers (ITS) 1 and 2 and the 5·8S gene. Parsimony and Bayesian approaches were used. • Key Results A close correlation between geography and the phylogenetic tree based on ITS sequences was found in all the analyses, with three main groups being resolved: (1) comprising the most widely distributed circum-Mediterranean/Eurosiberian sections; (2) the western Mediterranean sections; and (3) the eastern Mediterranean and Irano-Turanian sections. The results show that the sectional classification in current use needs major revision, with many old sections being merged into larger ones. A large polytomy in the eastern Mediterranean clade suggests a rapid and recent speciation in this group. Some inconsistencies between morphology and molecular phylogeny may indicate that hybridization has played a major role in the evolution of the genus. • Conclusions Phylogenetic analysis of ITS has been useful in identifying the major lineages in the group, and unraveling many inconsistencies in the sectional classification. However, most recent groups in the eastern Mediterranean clade are not resolved and reticulation in the western Mediterranean group of sections makes phylogenetic relationships within these two groups somewhat obscure.