Phylogenetic analysis and differentiation of Veronica subgenus Stenocarpon in the Balkan Peninsula

The Balkan Peninsula is considered the most important refugium for species during the Pleistocene glaciations and today harbours c. 2000 endemic species, but we know surprisingly little about the evolution of taxa in this region. Veronica saturejoides, V. thessalica and V. erinoides are a group of closely related alpine taxa endemic to the Balkan Peninsula. Here, we analyse four DNA regions the nuclear chalcone synthase intron (CHSi) and ribosomal internal transcribed spacer (ITS) region and the plastid rpoB‐trnC spacer and trnL‐trnL‐trnF region] and amplified fragment length polymorphism (AFLP) fingerprints to provide a phylogenetic hypothesis for the relationships among these taxa. Additionally, we analyse leaf morphological characters used to distinguish the three subspecies of V. saturejoides. The analyses support the distinction of the three subspecies based on previously intuitively suggested characters. Nuclear chalcone synthase intron data indicate that the southern taxa are genetically much more diverse than the more northern V. saturejoides subsp. saturejoides. Phylogenetic relationships inferred from this region and AFLP fingerprints support the monophyly of V. saturejoides. In contrast, plastid DNA regions suggest a closer relationship of V. saturejoides subsp. saturejoides to V. thessalica. The most likely scenario involves introgression into V. saturejoides subsp. saturejoides from V. thessalica. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 616–636.