Figure 1

Locations of sampled populations and species distributions. (a) Open circles represent Rubus palmatus sample locations (pKG, pBS, pEB, pKD, and pYK), and closed circles indicate sample locations of R. grayanus (gOK, gAM, gYK, and gTN). R. palmatus southern limits (solid line) and R. grayanus northern limits (dashed line) are shown. Geographic coordinates and altitudes are given in Table 1. (b) Sampled populations along altitudes on Yakushima, where the two species’ distributions merged, are indicated as shaded squares (ab1, ab2, ab3, ab4, ab5, pYK* on Anbo Lane, and sr1, sr2, sr3, sr4 on Shiratani Lane). Some individuals from the pYK population (pYK*) were located along Anbo Lane at high altitude and included in the analysis of the contact zones. The dashed line indicates the approximate sampling areas for pYK and gYK populations.