Phylogeography of Dianthus sylvestris and D. ciliatus
Dianthus is the second largest genus in Caryophyllaceae and a major group in Caryophyllales. It comprises more than 330 species distributed in Eurasia and Africa, and the new species are still being described. The vast majority of the species of Dianthus occur in Eurasia and originated through what has been described as one of the fastest radiation of flowering plants. The rapid increase in diversification within the Eurasian clade of Dianthus is accompanied with the complex evolutionary history of closely related species groups underlying the formation of labile boundaries among recognizable taxonomic entities. Key morphological characters to distinguish species are leaf shape and dimensions, flower number and organisation, size and form of the epicalyx, characters of the calyx, and appearance of the petals. However, most of these characters are often represented by more or less continuous variation rather than discrete character states, and may fail to reflect phylogenetic-systematically natural groups. Therefore, there is a need for an updated and comprehensive revision of the systematics of Dianthus groups. The Balkan Peninsula is one of the diversity centres for the morphologically highly variable and taxonomically inconsistently treated D. sylvestris and its sister species D. ciliatus. Both species have several recognized subspecies reflecting the morphologically high intraspecific diversity. Populations of D. sylvestris are mostly diploid (2n = 2x = 30) with only few tetraploid populations recently discovered in geographically small area in northwestern Balkan Peninsula. On the other hand, D. ciliatus populations are mostly tetraploid, occurring on the Apennine and the Balkan peninsulas, and diploid populations more restricted in two separate areas in the northwestern and southern Balkan Peninsula.  This integrative study uses an array of methods ranging from nomenclatural revision and morphometrics, following with phylogeographic methods (RADseq) and environmental niche analyses, to genome size estimates in order to explore the intraspecific relationships within and among this sister taxa. Within the research, the phylogeographic and historical processes that contributed to the observed genetic divergence patterns in this group are investigated and sensible taxonomic solutions are outlined.