Thalictrum acutifolium (Hand.-Mazz.) B. Boivin: a new record to the flora of the Jeju-do, Korea

Thalictrum acutifolium (Hand.-Mazz.) B. Boivin is hitherto known as an endemic species of China. However, recently we found another population in Jeju-do, Korea. This species is closely related to Thalictrum tuberiferum Maxim., having characters such as 2- or 3-ternate leaves, whitish stamens with clavate filaments, and stipitate achenes, but distinguished from the latter by the following features: rootlets lacking tubers, stoloniferous, alternate cauline leaves, apex acuted leaflets, and ovate-shaped sepals with whitish color. Here, we provide its description, illustrations, and photographs as a new record species in Korea. Also, a lectotype is designated for T. acutifolium based on the material conserved at the University of Vienna (WU).