Morphological and chemical evidence of Teucrium x rohlenae K.Malý (Lamiaceae), a new hybrid in Croatia

Several natural hybrids of Teucrium montanum L. and T. polium L. have been described in certain parts of the area where these two species are sympatric. A new population with intermediate individuals that share morphological characteristics of both T. montanum and T. polium has been found in Croatia (Bisko near Trilj), and most likely represents a hybridogenous taxon. The aim of this study is to compare the morpho-anatomical and phytochemical characteristics of the two parental species and their putative hybrid, as well as to determine the most important distinguishing characters between these three groups. In order to describe the variability and significance of morpho-anatomical and phytochemical differentiation of the analysed groups several multivariate statistical analysis were conducted (PCA, CDA, DFA, UPGMA-clustering). All analyses confirm the separation of two species, T. polium and T. montanum, and reveal the intermediate position of the putative hybrid. In this way, data on morphological and anatomical analysis together with data on the composition of the essential oils support the assumption of the hybridogenous origin of the intermediate individuals. Based on descriptions and original indication of parental species of previously described hybrids T. × castrense Verg., T. × bogoutdinovae Melinkov and T. × rohlenae K.Malý, we found that the intermediate specimens collected in Croatia perfectly correspond to T. × rohlenae, a hybridogenous taxon discovered by Rohlena in the vicinity of Kotor in Montenegro, and thus prove the presence of a new natural hybrid in the flora of Croatia.