The evolution of the Aristolochia pallida complex (Aristolochiaceae) contradicts traditional taxonomy and reflects large-scale glacial refugia in the Mediterranean

The taxonomy of the Mediterranean Aristolochia pallida complex has been under debate for several decades with the following species currently recognized: A. pallida, A. lutea, A. nardiana, A. microstoma, A. merxmuelleri, A. croatica and A. castellana. These taxa are distributed from Iberia to Turkey. To reconstruct phylogenetic and biogeographic patterns, we employed cpDNA sequence variation using both non-coding (intron and spacer) and protein-coding regions (i.e. trnK intron, matK gene and trnK-psbA spacer). Our results show that the morphology-based traditional taxonomy was not corroborated by our phylogenetic analyses. Aristolochia pallida, A. lutea, A. nardiana and A. microstoma were not monophyletic. Instead, strong geographic signals were detected. Two major clades, one exclusively occurring in Greece and a second one of pan-Mediterranean distribution, were found. Several subclades distributed in Greece, NW Turkey, Italy, as well as amphi-Adriatic subclades and a subgroup of sout...