Článek přestavuje taxonomicky problematický rod chrpa z čeledi Asteraceae. Jsou diskutovány současné pohledy na vymezení a vnitřní členění rodu založené na molekulárních znacích. Dále je popsána problematika hybridizace, která je v rodu velmi častá, a její souvislost s polyploidií (druhy stejné ploidie se často kříží za vzniku rozsáhlých a variabilních hybridních rojů, zatímco mezi ploidiemi je silná reprodukční bariéra).

Použitá a citovaná literatura:
Danihelka J., Chrtek J. & Kaplan Z. (2012): Checklist of vascular plants of the Czech Republic. – Preslia 84: 647–811.
Dostál J. (1976): Centaurea L. – In: Tutin T. G., Heywood V. H., Burges N. A., Valentine D. H., Walters S. M. et Webb D. A. (eds.), Flora Europaea 4: 254–301, Cambridge University Press, Cambridge.
Dostál J. (1989): Nová květena ČSSR. I, II. – Academia, Praha.
Garcia-Jacas N., Susanna A., Garnatje T. & Vilatersana R. (2001): Generic delimitation and phylogeny of the subtribe Centaureinae (Asteraceae): a combined nuclear and chloroplast DNA analysis. – Annals of Botany 87: 503–515.
Garcia-Jacas N., Uysal T., Romaschenko K., Suárez-Santiago V. N., Ertuğrul K. & Susanna A. (2006): Centaurea revisited: A molecular survey of the Jacea group. – Annals of Botany 98: 741–53.
Hardy O. J., de Loose. M., Vekemans X. & Meerts P. (2001): Allozyme segregation and inter-cytotype reproductive barriers in the polyploid complex Centaurea jacea. – Heredity 87: 136–145.
Hellwig F. H. (2004): Centaureinae (Asteraceae) in the Mediterranean – history of ecogeographical radiation. – Plant Systematics and Evolution 246: 137–162.
Koutecký P., Baďurová T., Štech M., Košnar J. & Karásek J. (2011): Hybridization between diploid Centaurea pseudophrygia and tetraploid C. jacea (Asteraceae): the role of mixed pollination, unreduced gametes, and mentor effects. - Biological Journal of the Linnean Society 104: 93-106.
Koutecký P., Štěpánek J. & Baďurová T. (2012): Differentiation between diploid and tetraploid Centaurea phrygia: mating barriers, morphology, and geographic distribution. – Preslia 84: 1-32.
Mráz P., Garcia-Jacas N., Gex-Fabry E., Susanna A., Barres L. & Müller-Schärer H. (2012): Allopolyploid origin of highly invasive Centaurea stoebe s.l. (Asteraceae) – Molecular Phylogenetics and Evolution 62: 612–623.
Mráz P., Španiel S., Keller A., Bowmann G., Farkas A., Šingliarová B., Rohr R. P., Broennimann O. & Müller-Schärer H. (2012): Anthropogenic disturbance as a driver of microspatial and microhabitat segregation of cytotypes of Centaurea stoebe and cytotype interactions in secondary contact zones. – Annals of Botany 110: 615–27.
Olšavská K. & Löser C. J. (2013): Mating system and hybridization of the Cyanus triumfetti and C . montanus groups (Asteraceae). – Folia Geobotanica 48: 537–554.
Olšavská K., Perný M., Španiel S. & Šingliarová B. (2012): Nuclear DNA content variation among perennial taxa of the genus Cyanus (Asteraceae) in Central Europe and adjacent areas. – Plant Systematics and Evolution 298: 1463–1482.
Susanna A. & Garcia-Jacas N. (2009): Cardueae (Carduoideae). – In: Funk V. A., Susanna A., Stuessy T. F. & Bayer R. J. (eds), Systematics, evolution, and biogeography of Compositae, p. 293–313, International Association for Plant Taxonomy, Wien.
Štěpánek J. & Koutecký P. (2004): Centaurea L. – In: Slavík B. & Štěpánková J. (eds), Květena České republiky 7: 426–449, Academia, Praha.

Centaurea is a taxonomically critical genus from the Asteraceae family. Current delimitation of the genus and its internal classi­fication based on molecular data are discussed. Hybridization and polyploidy are common in Centaurea. The frequency of hybridization depends on ploidy levels of the taxa (homoploid taxa usually hybridize easily and form extensive and variable hybrid swarms, while heteroploid taxa are reproductively strongly isolated).