Leaf morphology
All individuals from the Bonin Islands were subjected to leaf phenotypic analysis, except population SGi, which lacked collected sunlit leaves. For each individual, 1–5 leaves were measured for the same 11 traits outlined by Setsuko et al. (2023): total length, blade length, blade width, hair density on the upper and lower surfaces of the leaf (i.e., number of hairs per 4 mm2), number of serrations per 30 mm, thickness of the leaf blade, leaf area, leaf mass per area, ratio of blade length to total leaf length, and ratio of leaf blade width to length. Principal component analysis (PCA) was performed on the measured traits. The two individuals from the Mukojima Islands that exhibited an admixed pattern were excluded from PCA (Figs. 1 and 2).
RESULTS