Editing Centaurea (section)

==Systematics and taxonomy==
[[File:Centaurea horrida Sardinia LM022.jpg|thumb|''[[Centaurea horrida]]'']]
As namesake member of the [[subtribe]] [[Centaureinae]] of [[tribe (biology)|tribe]] [[Cardueae]], the knapweeds are probably most closely related to genera such as ''[[Carthamus]]'' (distaff thistles), ''[[Cnicus]]'' (blessed thistle), ''[[Crupina]]'' (crupinas) or ''[[Notobasis]]'' (Syrian thistle), and somewhat less closely to most other [[thistle]]s. The [[monotypic]] ''Cnicus'' seems in fact to properly belong in ''Centaurea''.<ref>Panero & Funk (2002), Keil (2006), Keil & Ochsmann (2006).</ref>

Research in the late 20th century shows that ''Centaurea'' as traditionally defined is [[polyphyletic]]. A number of 19th- and 20th-century efforts to reorganize the genus were not successful, and it is not yet clear what the consequences of the recent research will be for classification of this genus and other related genera. The [[type species]] ''[[Centaurea centaurium|C. centaurium]]'' stands somewhat apart from the main lineage of knapweeds and thus the [[Taxonomy (biology)|taxonomic]] consequences of a rearrangement might be severe, with hundreds of species needing to be moved to new genera. It has thus been proposed to change the type species to one of the main lineages to avoid this problem. What seems certain however is that the basketflowers &ndash; presently treated as a [[section (botany)|section]] ''Plectocephalus'' &ndash; will be reinstated as a distinct genus in the near future. The [[rock-centauries]] (''Cheirolophus''), formerly usually included in ''Centaurea'', are now already treated as separate genus.<ref name=kko2006/>

<gallery>
File:Centaurea macrocephala cropped-2832.jpg|Globe knapweed (''[[Centaurea macrocephala|C. macrocephala]]'')
File:Centaurea napifolia Sardinia LM.jpg|''[[Centaurea napifolia]]''
File:Centaurea nervosa (fabrizio.binello).jpg|''[[Centaurea nervosa]]''
File:Centaurea pseudophrygia DSCF1538.JPG|''[[Centaurea pseudophrygia]]''
File:Centaurea pulcherrima0.jpg|''[[Centaurea pulcherrima]]''
File:Centaurea triumfettii.jpeg|''[[Centaurea triumfettii]]''
File:0 Centaurea uniflora - Centaurée à un capitule.JPG|''[[Centaurea uniflora]]''
</gallery>