Adenostemma madurense DC. (Asteraceae, Adenostemma L.), which is known to be distributed in Japan, Taiwan, Thailand and Nepal was recently found on Jeju Island in Korea. It is morphologically allied to A. madurense but distinguished from A. lavenia (L.) Kuntze by having such characters as broadly ovate or ovate to oblong leaves, 15-21 ㎝ long × 7-12 ㎝ wide and smooth achenes with slightly muricate at the upper. Furthermore, A. madurense is found in dry mountain slopes in evergreen forests while Adenostemma lavenia occures in the wetland and side of pond. This taxon was named ‘San-mul-meo-wi’ in Korean based on its habitat. We provide a description, illustrations, photographs, and the key to the related species in Korea.

• Keum Seon Jeong(Division of Forest Biodiversity and Herbarium, Korea National Arboretum, Pocheon 11186, Korea)
• Tae Im heo(Division of Plant Conservation, Korea National Arboretum, Pocheon 11186, Korea)
• Kang Hyup Lee(Division of Forest Biodiversity and Herbarium, Korea National Arboretum, Pocheon 11186, Korea)
• Kyung Choi(Division of Forest Biodiversity and Herbarium, Korea National Arboretum, Pocheon 11186, Korea)
• Hyuk-Jin Kim(Division of Forest Biodiversity and Herbarium, Korea National Arboretum, Pocheon 11186, Korea) Corresponding author