(1) Plants in the crater of Halla-San (Mt. Halla), a conical volcano that originated in the Tertiary period, were studied on three different occasions; July 1937, July 1955, and August 1957, and noted 52 familites, 149 species. In the latest study undergone in 1957, the authors collected 108 species. Notable species among them are Geranium Shikokianum Matsum which has not been reported in Korea, Clematis Chiisanensis Nakai, Lactuca Chelidonifolia Makino, and Platanthera Maximowiczana Schelchter which have not been reported in Jeu-Do(Island) so far. (2) Plants in To-Do(Island), territorial island of Jeju-do, were also studied. The authors noted Canavalia lineata D.C.non-reported Species in Korea, usually distributed along Southern Honshu, Shikoku, and Kyushu of Japna, Ryukyu and Taiwan. The overfall flora of the island is composed of 30 families, 44 Species; 5 Species of wood plants and 39 species of herbs, and is mostly of littoral plants.