北海道の古第三紀ブナ化石 <Bull. Natn. Sci. Mus., Tokyo>Fagaceous Leaves from the Paleogene of Hokkaido, Japan

Fossils of the Fagaceae are uncommon in the Eocene of Hokkaido, although commonly known in the Oligocene. These Paleogene Fagaceae species are composed of 3 extant genera (Castanea, Fagus and Quercus), 1 extinct genus (Fagopsis), and 1 form-genus (Dryophyllum); 11 identified taxa of this family include 8 new species. All the taxa are represented by leaf impressions, except a poorly preserved cupule of Quercus. The stratigraphic distribution of these Paleogene taxa of Hokkaido indicates that the genus Fagus and Castanea first appeared in the Early Oligocene, and that the genus Quercus appeared in the late Middle Eocene, and then markedly diversified since the Early Oligocene. Considering these occurrence together with fossil record of other regions, Paleogene history of the Fagaceae in East Asia is briefly summarized.