Phylogenetic analysis of Santolina genus

The genus Santolina L. (Asteraceae, Anthemidae) is distributed in the western part of the Mediterranean basin. The taxonomic history is long and complex: currently the whole genus comprises 29 taxa, most of which are divided in two complexes: the S. rosmarinifolia one, which includes eleven taxa endemic to Iberian Peninsula and North Africa and was subject of extensive systematic and phylogenetic analysis, and the S. chamaecyparissus one, which includes fourteen, mainly narrow endemic, taxa occurring in Spain, France, and Italy. Four taxa are not included in either complexes. Here we presented for the first time a phylogenetic analysis of the whole genus based on genetic data obtained through RADseq. To investigated genome‐wide diversity structure we computed a co‐ancestry matrix between individuals with RADpainter software and by performed a principal component analyses of genotypes. To assess evidence of historical gene flow, we performed an ABBA‐BABA test using Dsuite package. Our phylogeny recognizeed two main well‐supported clades in Santolina roughly coinciding with the two main morphological complexes. S. villosa belonging to the latter complex, shared a common ancestry with species of S. rosmarinifolia complex. We provided a first assessment of the taxonomic position of S. africana, a species omitted from all previous taxonomic surveys because of its mixed morphological features, now resulting sister to the S. chamaecyparissus complex. In conclusion, we build the first phylogenetic hypothesis for the Santolina chamaecyparissus complex. Taken together our results set the stage for further investigations of the evolutionary history of this circum‐Mediterranean group.