Microscopic Leaf Constant Numbers of Chromolaena odorata in Thailand

Introduction: Chromolaena odorata (L.) R.M. King and H. Rob. (syn. Eupatorium odoratum L.), commonly known as Siam Weed, Christmas Bush, or Common Floss Flower, is a species in family Asteraceae. It has been widely used as medicinal plants for a long time. In Thailand, C. odorata is locally used to treat skin diseases and insect bites. Leave juice from the crushed leaves can be used as a haemostatic and anti-inflammatory in the treatment of skin wounds. Objective: This study aimed to investigate the leaf constant values of microscopic characters of leaf in term of stomatal number, stomatal index, epidermal cell number, trichome number, trichome index and oil gland number of C. odorata in Thailand. Method: Microscopic evaluation of leaf constants are frequency used for the medicinal plant samples. Leaf constant numbers used to identify between some closely related species. Light microscope (LM) attached a digital camera and scanning electron microscope (SEM) were used in this study. Results and Conclusion: The results showed anomocytic stomata and multicellular non-glandular trichomes on both upper and lower epidermis of C. odorata, while oil glands were found on only lower epidermis of the leaf. The microscopic leaf constant numbers of C. odorata were established and could be used for the species identification of C. odorata in Thailand.