Two Genotypes of Pedicularis chamissonis (Scrophulariaceae) Distributed at Mt. Gassan, Japan: Additional Genetic and Morphological Studies

Pedicularis chamissonis

Steven, which is broadly distributed from northern Honshu of Japan to southwest Alaska, is known to comprise a few different cpDNA haplotypes grouped into two major (“Northern” and “Southern”) clades. This paper presents on the basis of chloroplast and nuclear DNA analyses that no gene flow exists between the two clades at Mt Gassan where two haplotypes D and J of the Northern and Southern clades occur. The two haplotypes are further distinguished from each other in corolla and leaf shape and the number of flower whorls on an inflorescence axis, a fact indicating that individuals of the two clades should be treated as separate species. At Mt. Gassan and in other regions in general the haplotypes of the Southern clade currently grow at higher altitudes than those of the Northern clade. Based on the difference in habitat as well as the lack of gene flow between the two clades, evolutionary processes resulting in the current distribution of the two genotypes are also briefly discussed.