This study was survey a flora and life form spectrum of 11 uninhabited islets, in jeju-do. The vascular plants of each uninhabited islets were summarized as Beomseom 159 taxa, Chagwi-do 136 taxa, Daryeo-do 81 taxa, Hyeongje-do 61 taxa, Jigwi-do 39 taxa, Munseom 147 taxa, Ran-do 58 taxa, Saeseom 65 taxa, Seogeondo 60 taxa, Seopseom 183 taxa and Wa-do 46 taxa. Floristic richness was in order analyzed to be Seogeon-do 28.62, Ran-do 19.24, Daryeo-do 18.53, Wa-do 16.42, Munseom 16.14, Hyeongje-do 14.76, Seopseom 13.32, Beomseom 13.24, Chagwi-do 6.15, Saeseom 5.86 and Jigwi-do 2.51. Life form spectrum was surveyed to H-D5-R4-e; hemieryptophyte(H) 26.8％, not production seeds(D5) 54.4％, clonal growth by stolons and struck roots(R4) 46.9％ and erect form(e) 30.3％. According to the life form spectrum hemieryptophyte dominated high portions, which suggests islet in jeju-do has hemieryptophytic climate and similar to middle parts in Korean Peninsular. However, were noticed by that it has more therophytes. As a result, Partially shows the characteristics change from the temperate climate to the warm temperate climate or a semitropical climate by a climatic change.

This study was conducted to provide scientific information for establishing efficient and systematic measures for nature conservation and management in Manjang-gul lava tube. The number of vascular plants was 204 taxa (82 families, 176 genera, 144 species, 1 subspecies, 26 varieties and 1 forma). Of those, pteridophyte were 5 families, 12 genera, 14 species and 1 variety and gymnosperm were 4 families, 6 genera, 5 species and 1 variety. Seventy three families, 149 genera, 157 species, 1 subspecies, 24 varieties and 1 forma in angiosperm composed of 62 families, 123 genera, 137 species, 1 subspecies, 17 varieties and 1 forma in dicotyledon and 11 families, 26 genera, 20 species and 7 varieties in monocotyledon. The number of naturalized plants was 9 families, 17 genera, 18 species and 3 varieties, totaling 21 taxa.