The phylogeny and biogeography of Gentiana L. sect. Ciminalis (Adans.) Dumort.: A historical interpretation of distribution ranges in the European high mountains

Gentiana sect. Ciminalis consists of seven mostly ecologically or geographically vicariant and closely related species which are distributed throughout the South and Central European high mountains. The analysis of a RAPD data set and trn L-intron and ITS sequences resulted in slightly different phylogenetic hypotheses. In the preferred hypothesis the group consists of two completely resolved main lineages: 1) G. clusii and G. alpina. 2) G. dinarica, G. acaulis, G. ligustica, G. angustifolia and G. occidentalis. The most important conclusions we have drawn from this phylogenetic hypothesis and from the observed patterns of molecular variation are: 1) The calcifuge ecology of G. acaulis and G. alpina evolved independently from calcicole ancestors. 2) Among the calcicole taxa speciation proceeded from East to West in a simple vicariant pattern. 3) The application of a provisional molecular clock indicates that speciation events in sect. Ciminalis probably occurred in the Quaternary. 4) Differences in infraspecific genetic variation among the widespread species suggest that G. alpina probably experienced more recent dispersal or gene flow than G. clusii and G. acaulis. 5) The large number of mutations in the lineage leading to G. angustifolia, compared to the few mutations in the lineage leading to G. dinarica, may be a result of their different population histories. While the extant range of G. angustifolia was strongly affected by Quaternary climatic fluctuations, that of G. dinarica has had a more stable climatic history. 6) The low number of mutations and the basal position in one clade of the preferred cladogram leads to the conclusion that G. dinarica is the species most similar to the last common ancestor of sect. Ciminalis.