Population dynamics of Trillium species in Tohoku district in Japan : I. The field and chromosome researches from the Sashimaki marshland near Lake Tazawa in Akita

Abstract

About 1,000 plants of Trillium camschatcense (2n=2x=10) are growing well in the Sashimaki marshland (5 hectare area) near Lake Tazawa in Tohoku district. These plants are located in the most southern limit of their distributions (Trillium camschatcense). 13 plants of Trillium apetalon (2n=4x=20) also grow there. Only 3 plants of Trillium yezoense (2n=3x=15) have been found growing in this area. By means of chromosome analysis of cold-induced banding karyotype, it has been confirmed that their plants are hybrid between T. camschatcense and T. apetalon.