Comparative Anatomical Studies on Three Tanacetum L. Taxa (Asteraceae) Growing in Turkey

Tanacetum L. (Asteraceae) is a complex genus represented by 160 species in the world and 47 species in our country. Tanacetum parthenium (L.) Sch.Bip., among the species of this genus which have been used in traditional treatments, is an official species registered in many pharmacopoeia and monographs due to its parthenolide content. Studies have shown that subspecies of T. argenteum (Lam.) Willd. also contain parthenolide as the major active constituent. In this study, besides the well known T. parthenium, the anatomical characteristics of parthenolide-containing taxa with therapeutic potential; T. argenteum (Lam.) Willd. ssp. canum (C.Koch) var. pumilum and T. argenteum (Lam.) Willd. ssp. flabellifolium (Boiss. & Heldr.) Grierson were also investigated for the first time. The transverse and superficial sections taken from the stems and leaves of the taxa were examined by light microscope and specific anatomical features were defined. Uniserial, multicellular covering hairs on stem and leaf surface and bifacial leaf structure are the most prominent characters that distinguish T. parthenium from other studied taxa. There was no significant anatomical difference found between the two infraspecific taxa of T. argenteum