Genetic diversity and its conservation implications of (Lamiaceae) populations in East Asia.

is an important coastal and medicinal plant, and is recorded in the List of the Important Wild Plants for Conservation in China and Japan. However, an effective conservation strategy is lacking. In the present study, the genetic diversity and population structure were analyzed using phylogeographical methods based on the and intergenic spacers of the chloroplast DNA (cpDNA) sequences from 157 individuals from 25 sampling sites for and plus the internal transcribed spacer (ITS) of the nuclear ribosomal DNA (nrDNA) sequences of 177 individuals from 27 sampling sites. The results showed that and had eight cpDNA and two nrDNA haplotypes, respectively, and the has a low level of genetic diversity (haplotype diversity = 0.360, = 0.440), a more pronounced genetic differentiation among populations (population differentiation at the species level ( ) = 0.201, population differentiation at the allele level ( ) = 0.462), and an insignificantly different phylogeographical structure ( > ,  > 0.05). In addition, haplotype network analyses indicated that and have distinct haplotypes. Divergence dating based on BEAST software analyses showed that most cpDNA clades diverged in the late Pleistocene era. Demographic analysis indicated that underwent a rapid demographic expansion. Some scientific strategies are suggested for resource conservation of based on its genetic diversity and population structure.