Anatomical and micromorphological properties of some Tanacetum L. (Asteraceae) taxa from Turkey and their systematic implications

Abstract

In this study, the anatomy and trichome micromorphology of Tanacetum macrophyllum (Waldst.&Kit.) Schultz, T. parthenium (L.) Schultz, T. poteriifolium (Ledeb.) Grierson and T. vulgare L. were examined by light microscopy and scanning electron microscopy. Some anatomical characters such as presence of secretory cavities and pith in root and mesophyll type in leaf provide information of taxonomical significance. In addition, the existence of a parenchymatic layer, which consists of elongated parenchymatic cells in the stem of T. macrophyllum, is a distinguishing character. The results obtained from scanning electron microscope studies showed that trichome micromorphology varies among examined taxa. In T. macrophyllum, the eglandular and glandular trichomes especially on disc florets, ligulate florets and cypselas are more sparse, whereas disc florets and cypselas of the other taxa are covered with abundant glandular trichomes. Additionally, T. poteriifolium and T. parthenium has a distinct distribution of glandular trichomes forming in a row across the entire cypsela surface.