AbstractCamellia japonica and Eurya japonica, broad-leaved evergreen woody plants, are widely distributed in eastern Asia. Eurya japonica is dioecious, whereas flowers of C. japonica are perfect. We investigated the spatial distribution of genotypes among 15 and 21 Korean populations of C. japonica and E. japonica using spatial autocorrelation analysis of enzyme polymorphisms to test the previous prediction that dioecy is a primary factor which increases interpopulational gene flow. The patterns of spatial genetic distribution among populations of both species are very similar: percentage of significant Moran's /values (15 vs. 17 for C. japonica and E. japonica) and percentage of significant overall correlogram (18 vs. 20 for C. japonica and E. japonica). For both species, the patterns of average Moran's/values for each distance class were very similar as in an isolation by distance model. It may be concluded that dioecy may not a primary factor in shaping spatial genetic structure in E. japonica. Instead, abundant and continuously distributed patterns observed in E. japonica and an occasional pollen transfer by birds between isolated island populations of C. japonica in Korea may play roles in shaping spatial genetic structure among Korean populations of the two species.