subfamily Gardennieae, family Rubiaceae. It is widely distributed in tropical and sub-tropical regions, especially in Asia and Africa. Craib reported that R. siamensis CRAIB is synonymous with R. longiflora HOOK f., R. uncata RIDL., Griffithia siamensis MIQ. and Webera siamensis KURZ. It can be found in all parts of Thailand and Burma, especially in humid regions. This plant is known by various...