Due to its morphological variability and high phenotypic plasticity, many species have been described that are considered synonyms or infraspecific taxa within the broadly defined Teucrium montanum. Although T. montanum has been the subject of numerous studies dealing with anatomy and phytochemistry, no taxonomic studies with extensive population sampling and detailed genetic analyses have been carried out. Therefore, the aim of this study is to perform a detailed morpho-anatomical, phytochemical and molecular analysis on an extensive population sample. A number of molecular techniques in combination with multivariate morphometry and qualitative and quantitative analyses of essential oils will be performed.