[Macroscopic and microscopic identification of Chinese herb belonging to genus Senecio]

The medicinal herbs derived from genus Senecio have been commonly used in Chinese medicine and triggered attention in recent decades for that they contain the hepatotoxic pyrrolizidine alkaloids. Therefore the botanical pharmacognostic study to authenticate those herbs based on their macroscopic and microscopic characteristics is important for the assurance of safety when they are applied as raw material for extracts or for finished products. In this paper, 13 taxa (11 species and 2 varieties) of Senecio plants were collected and their macroscopic and microscopic characteristics were observed and described by digital microscopic illustration. The results showed that the distribution of collenchyma in the cortex, the level of development for pericycle, the location of the phloem, and the ratio of pith in transverse sections of the stems, and the morphology of the leaf epidermal cells, the stomatal types and the non-glandular hairs in leaf surface view were found to be the main microscopic characteristics for authentication of different Senecio species. The herbs derived from genus Senecio can be distinguished from each other on the basis of their macroscopic and microscopic characteristics, and those observation can be used for the identification of commercial crude drugs from Senecio plants.