Macroscopic and Microscopic Identification of the Two Species of Atractylodis

Atractylodis Rhizoma, also known as Cangzhu (蒼術), is a traditional Chinese medicinal herb. It has been used for the treatment of abdominal distention, diarrhea and edema. This herb, however, has two species; namely Atractylodes Iancea (Thunb) DC (茅蒼術) and Atractylodes chinesis Koidz (北蒼術). Both species look alike and are not easily distinguishable by most people based on their appearance. To distinguish the two species and ensure their safety and efficacy, microscopic characteristics of rhizomes, including transverse sections, as well as the crude drug powder, were examined. The fixed, sectioned, and stained plant materials, as well as the crude powder, were studied using a light microscope according to the usual microscopic techniques. The results of the microscopic features were systematically and comparatively described and illustrated. The two species have distinct microscopic characteristic differences, thus allowing us to distinguish between the species and a comparative chart of the key authentication parameters based on these macroscopic and anatomic characteristics was drawn up and is presented for the Atractylodes species studied. The study indicated that light microscopy and related techniques provide a method that is convenient, feasible, and can be unambiguously applied to the authentication of species of Atractylodes.