Dual colonization of European high-altitude areas from Asia by Callianthemum (Ranunculaceae)

Floristic similarities between European and Asian mountain ranges have long been recognized, and the hypothesis that European mountain plant taxa immigrated from Asian mountain areas has been confirmed by several molecular phylogenetic analyses. Callianthemum contains ca. 14 species, of which ca. 11 are distributed in Asia and three in Europe. A molecular phylogenetic analysis of the genus using ITS and four plastid DNA sequences (matK, rpL32–trnL intergenic spacer, trnL– trnF intergenic spacer, trnV–ndhC intergenic spacer) revealed that the genus reached Europe twice, with C. coriandrifolium representing one, and C. anemonoides and C. kernerianum a second lineage. Support for C. anemonoides and C. kernerianum as sister species is weak. The crown group ages of the C. coriandrifolium lineage (median 2.2 million years) and of the C. anemonoides/C. kernerianum lineage (median 1.62 million years) are similar and place their immigration to Europe in the Quaternary. Analysis of climatic data shows that C. coriandrifolium grows in colder climate than C. anemonoides/C. kerneri- anum and that the climatic niches of the three European species are different considering all climatic variables analyzed.