A Scanning Electron Microscope Study of Vegetative Parts of the Genus Vincetoxicum in Türkiye

In Türkiye, Vincetoxicum is represented by 11 taxa belonging to nine species, three of which (V. coskuncelebiana S.Makbul & S.Güven, V. fuscatum (Hornem.) subsp. boissieri (Kusn.) Browicz, and V. parviflorum Decne) are endemics. In this study, the micro-morphology of the stem, petiole, and lamina of all Turkish Vincetoxicum taxa was examined using a scanning electron microscope (SEM) for the first time. Micro-morphological observations were carried out on herbarium samples belonging to 21 populations from various habitats. A detailed micro-morphological description of the stem, petiole, and lamina, supported by SEM micrographs, was created for each examined taxon. It was determined that the micro-morphological characteristics such as the pattern of pubescence, the distribution and density of trichomes on the stem, petiole, and lamina, and the position of stomata on both sides of the leaf contributed to the distinction of the Turkish Vincetoxicum taxa. On the other hand, no difference was observed among the examined taxa in terms of the appearance of epicuticular wax, and shape and concavity/convexity properties of epidermal cells on stem, petiole, and lamina.