A cytosystematic study of the Dianthus virgineus complex (Caryophyllaceae) in the Central Mediterranean

European wild carnations (Dianthus) are represented by a high number of taxa organized in unresolvedtaxonomies. In particular, taxa belonging to the Dianthus virgineus L. complex in the Central Mediterranean havebeen delimited mainly with qualitative morphological data and still await quantitative investigations, which are vital tounderstand boundaries and relations among plant diversity groups. Here, we examine the phenotypic features ofnuclear genome organization testing for species boundaries in this complex. We have studied the chromosomenumber, the total haploid length (THL), and the relative genome size (RGS) in 122 populations belonging to 25 out of33 taxa of the complex. All the studied populations have 2n = 2x = 30 chromosomes, and the THL ranges from 14.09to 20.71 μm. Genome size estimations support the absence of polyploidization events, but show a certain degree ofvariation (0.318–0.423 arbitrary units). The RGS variation is not in agreement with current taxonomic treatment, butrather shows a geographical pattern, with higher values in Sicily and Sardinia. No correlation between the THL andthe RGS was detected, possibly due to the stable chromosome number and the small size of chromosomes. Anumber of evolutionary unique groups lower than the number of currently accepted taxa may be hypothesized