Taxonomic study of some medicinally important species of Swertia L. (Gentianaceae) in Nepal

Among 100 species of Swertia reported from the world, Nepal harbors 30 species along with four varieties. In Nepal, species of Swertia are highly exploited as raw materials for different traditional medicines. Among them, S. chirayita, a vulnerable species, has been considered to be superior in medicine and trade. One of the main issues in its trade is adulteration with other species which are considered to be inferior in medicinal quality. Species which are mixed with S. chirayita are S. angustifolia, S. ciliata, S. dilatata, S. paniculata, S. racemosa, etc. There is a need for the selection of most important morphological characteristics for instant identification of different species of Swertia to check illegal trade as well as adulteration. This paper aims to provide the most important identifying characters of eight species of Swertia traded from Nepal on the basis of their morphological studies. Color of the petal, number of floral parts (tetramerous vs. pentamerous) and number of glands in petal are the key characters for the identification of the species.