Distribution of chloroplast DNA haplotypes in the contact zone of Fagus crenata in the southwest of Kanto District, Japan.

We have investigated cpDNA haplotype distribution in 24 populations of Fagus crenata in the southwest of Kanto District, Japan, and clarified the extent of intermixing of haplotypes in the contact zone by additional fine-scale analysis of two areas. Two cpDNA haplotypes belonging to different lineages were detected, and their distribution had geographical structure. Intermixed populations with the two haplotypes were limited to a narrow area. The geographical boundary between the haplotypes extended from Hakone to the west of the Kanto Mountains through the northern foot of Mt Fuji. No relationship was observed between the boundary location and the current topography of the southwest of Kanto District.