Radicoid structure of herbaceous communities in Mt. Kumbyung, Chunchon, Kangwon-Do was clarified emphasizing on the dominance of clonal plants in relation to vegetation development. In the total vegetation, 46% species identified were rhizomatous, 26% were species with tap roots, and 13% were stoloniferous species. Thus, all clonal species, including plants with bulb, corm and tuber, covered 62.8% of the total species. in the understory of Quercus, Pinus and Larix forests, 68.2% were clonal, which means 5% more compare to total vegetaion. Dominance of clonal plants became more conspicuous as their importance value was calculated. That is, they covered average 86% for the following three communities: 85% in Quercus, 95% in Pinus, and 76% in Larix, Especially, the rhizomatous plants were remarkable. Overall, clonal species dominated over the other radicoid types in terms of not only the number of species, but also the importance value. Dominance of these species was more peculiar in understory of forests, indicating the occupancy of clonal plants was related to the vegetation development.