We investigated the morphological and genetic variations found in Suaeda maritima growing on sand dunes at Jogeum-naru, Muan-gun, in Korea. Our objective was to determine how plant density, biomass, and morphological characteristics were affected by habitat and environmental factors. Differences in elevation dictated that habitats for this species be divided into three positions: low, middle, and high areas. The higher the elevation, the lower the amount of available water, total nitrogen, phosphate, and organic matter. Correlations between biomass and environment were statistically significant. For example, plant density and biomass declined as elevation increased. In low areas, the lengths of aerial stems and leaves were 17.98_+0.46 and 7.83_+0.12 mm, respectively; values measured at high areas were 0.70 and 0.83 times smaller, respectively. Likewise, lengths of main roots in low areas were 8.06__. 0.21 ram; in higher areas, roots were 1.58 times longer. Leaf widths in low areas were 1.88_+0.01 ram, and 1.16 times greater at higher elevations. Values for these parameters in middle areas were intermediate between those for the other two. Nevertheless, when we used an MVSP computer program to conduct a similarity coefficient analysis, we found that the morphological variations recorded at the three elevations were not matched by differences in DNA patterns, although genetic variations were observed within individual populations.