Abstract
The genetic relationships between the Higashi-Iyayama population and some other populations of Ranunculus japonicus, and two other closely related species, R. yakushimensis and R. acris var. nipponicus, were assessed morphologically, karyotypically, electrophoretically and by cross experiments. Plants of the Higashi-Iyayama population showed a leaf shape and the flowering time being similar to those of other R. japonicus populations but different from those of R. acris var. nipponicus and R. yakushimensis populations. On the other hand, plants of the Higashi-Iyayama population differed from those of other R. japonicus populations in both achene shape and plant size. These results suggest that plants of the Higashi-Iyayama population are not hybrids between R. japonicus and R. acris var. nipponicus, but rather are derivatives with some new characters from R. japonicus. The allozymic analysis and cross experiments show that the Higashi-Iyayama population is closely related to those of other R. japonicus and R. yakushimensis, but less closely to those of R. acris var. nipponicus.
