125. Studies on the Cenozoic Plants of Hokkaidô and Karahuto. VII.

On the Tertiary Marlea (=Alangium) from Hokkaidô and Karahuto. (Preliminary Report)

Abstract

There are about. eight living species of Marlea (=Alangium) distributing in Japan, Manchoukuo, China, and palaeotropical region of southeastern Asia. Of these, M. platanifolia SIEB. and Zucc. and M. chinensis REHDER are living in the Japanese Islands, the northern most limit of the former being Prov. Kitami (N. L. 45°) of ilokkaido, while the latter the southern Kyusyfi (Ni.32°).
The authors recognized four different types of fossil Marlea from the Tertiary rocks of Hokkaido and Karahuto. They are M. basitruncata sp. nov., M. kusiroensis sp. nov., M. taiheiensis sp. nov. and M. basiobliqua sp. nov. The former three are the type of modern M. platawfolia, while the last one is the type similar to Al. chinensis. Al. basitruncata and M. basiobliqua have been derived from the Woodwardia Sandstone of the Isikari Series of Hokkaido (lsika, rian Stage ; Palaeogene), M. kusiroensis from the Syakubetu coal-bearing beds of the TJrahoro Series of Hokk. aidli (Urahorian Stage; Oligocene-Miocene) and M. taiheiensis from the Esutoru coal-bearing bels of Karahuto (Kawabataian Stage; Miocene).
In 1939, KRYSHTOFOVICH and BORSUS brought Ficus tiliaefolia (Al. BR.) HEER and Biittneria aequalifolia (GOEPP.) MEYER into one species and adopted the generic name Alangium taking the latter specific name. The present authors agree with these Russian authors in that the genus Alagium (=Marlea) is the more adequate generic designation for the named fossil types, yet the present authors bear a different opinion in bringing them into one specific type. Types referable to “Buttneria aequalifolia” are rather common in the Kawabataian flota of Hokkaidô and Karahuto, but the comparison with the living types bearing similar foliar characters is now carrying on.
The details may be printed in the Journal of Faculty of Science, Hokkaidô Imperial University.