A method for detecting the biosystematic significance of the essential oil composition: The case of five Hellenic Hypericum L. species

We examined the importance of the constitutive terpenoids of five species of Hypericum native to the Greek mainland, Crete Island and the west Aegean. The species studied are Hypericum empetrifolium Willd. (sect. Coridium Spach), Hypericum rumeliacum Boiss. subsp. apollinis Robson & Strid, Hypericum perfoliatum L. (sect. Drosocarpium Spach), Hypericum triquetrifolium Turra and Hypericum perforatum L. (sect. Hypericum, subsect. Hypericum [Robson, N.K.B., 2001. Studies in the genus Hypericum L. (Guttiferae). 4 (1). Sections 7. Roscyna to 9. Hypericum sensu lato (part 1). Bull. Brit. Mus. (Nat. Hist.) Bot. 31, 37–88]). Canonical discriminant analysis (CDA) on 98 of the most abundant terpenoids was found to achieve a separation of species. The performed phylogenetic reconstruction supports the existing divisions of Hypericum in taxonomic sections. Other multivariate techniques were also investigated such as principal coordinate analysis and principal component analysis, but these were found inferior to CDA. These analyses transformed the data in such a way that they did not sufficiently account for the entire terpenoid variation, nor did they delineate species in accepted taxonomic sections.