The genus Cheirolophus is a good example of a genus with a western Mediterranean distribution, with an important centre of speciation in Macaronesia. We carried out an electrophoretic study on representatives of Iberian-North African species of Cheirolophus as well as species from the Canaries. In addition, some species of the genera Centaurea, Crupina and Serratula were examined. Our results show high genetic identities between taxa and low genetic diversity in Cheirolophus from the Canaries. This is the same pattern found in plants from other oceanic archipelagos and it suggests a recent colonization of the Canaries by the genus Cheirolophus. The Iberian species exhibit high genetic identities, suggesting that the genus as a whole is yonnger than has been suggested. Cluster analysis shows little correlation between accepted taxonomic delimitation of the species of Cheirolophus and isozyme variation, which points towards very recent speciation in the genus; not only in the Canarian species, but also in the continental group. On the other hand, cluster analysis reinforces the segregation of Cheirolophus as a genus distinct from Centaurea and supports a closer relationship to the genus Serratula.

Peer reviewed

14 p.