Journal of the Faculty of Science, Hokkaido University. Series 4, Geology and mineralogy;Vol.XX, No.4


Revisions of Tertiary Acer from East Asia

Tanai, Toshimasa

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Although a number of Acer species were recorded in the Tertiary of East Asia, their nomenclature and systematics have been considerably confused. Examination of previously-described and some undescribed specimens indicates that 35 species including five new species are designated with certain modern realationships in East Asia. Beside them six doubtful species of Acer are lacking in the definite systematic indications, and there are many specimens which are too incomplete to assign their modern relationships. Thirty-five well-defined species are included in 17 sections, of which three sections have no living species in East Asia. Considering the stratigraphic range of each species together with past and present distribution, the phylogenetic history of Acer in East Asia is brieafly discussed. Three older lineages, the section Spicata, Rubra and Campestria, are confirmed. Other sections, excepting for Distyla, are rather young; most of them probably evolved from these three stocks, and some migrated from North America by long-distance dispersal.