Abstract
Some fossil samarae (text-figs. 2, 3, 4) belonging to the genus Ailanthus were discovered from the Kunnui series (Kawabataian; Miocene) of Abura, Prov. Siribesi. This is the first fossil occurrence of the genus in Japan, and palaeophytogeographically very interesting, because the genus does not exist in wild state in the Japanese Islands. Ailanthus now distributes rather widely in Asia and Australia, but its section Euailanthus of the subgen. Ailanthopsis, to which our fossil is belonged, grows only in China. Our fossil may be comparable to the living Ailanthus altibsima (MILL.) SWINGLE (fig, 1) of China and A. Confucii UNGER from the European Tertiary. The writers wish to suggest a new specific name, yezoense, for the present specimens.
