Abstract

Caryopteris incana, an endangered species distributed parts of western Kyushu in Japan, is composed of clusters of individuals that can be recognized as a population, and grow in a spatially isolated environment. The objective of this study was to evaluate the phenotypic variation of C. incana in western Kyushu and to clarify their relationships with natural environment and geographical structure, therefore, we investigated the growth survey using collected seeds under the same cultivation conditions. As a result, it was confirmed that each natural population showed various phenotypes in plant height, flower color, etc., and each population was classified into five groups by phenotype, showing the similar phenotype in each region. On the other hand, since different phenotypic groups were shown in the same region, it was inferred that each natural population acquired various phenotypes by differentiating independently in various natural environments. In addition, chloroplast DNA haplotypes differed between populations with the same phenotype, suggesting that they should be conserved as separate local populations to maintain genetic diversity. Similarly, because of the low seed-dispersal ability and the ecology as a lithophyte, even if haplotypes are common, when phenotypes differ between populations, they should be conserved as finely divided as possible. These results suggest that local populations and their ranges of high conservation priority should be set not only among regions but also within regions, and prompt actions should be taken.