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.
"Nikko-ohzumi", which was discovered at the side of Lake Chuzenji in Nikko (Tochigi Pref.) and described as a new variety, Malus baccata var. nikkoensis, by Asami(l927) but ignored for a long time, was rediscovered. A detailed morphological reexamination indicated that it is impossible to separate this variety from var. mandshurica by tooth height and shape of the sepals, which were considered to be the distinguishing characters by Asami. The geographical distribution of M. baccata var. mandshurica (including var. nikkoensis) in Honshu was also reexamined. Malus baccata var. mandshurica grows disjunctively in the northern Tohoku district, the Chubu district (Nagano Pref. and Yamanashi Pref.) and Nikko. At Nikko, only about 60 plants were discovered and it is questionable whether this population is regenerating.