A phylogenetic study of primitive angiosperms

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In this research project, the phylogeny of primitive angiosperms was studied from a viewpoint of paleobotany by M.Nishida, H.Nishida, Suzuki, and Takahashi as well as from a viewpoint of neobotany by Tobe, Ueda, Kosuge, and Oginuma.M.Nishida collected a permineralized angiosperm fructification from the Upper Cretaceous of Monbetsu-cho, Hokkaido and described its reproductive structure similar to the one of Magnoliales and paleoherbs ; H.Nishida collected a possibly dileniid angiosperm fructification from the Upper Cretaceous of Kodaira-cho, Hokkaido and discussed an evolutionary pathway from a magnoliid flower to a dileniid one ; Suzuki analyzed the possibly earliest dicotyledonous wood fossils from the Upper Cretaceous of Hokkaido, and of Saghalien of Russia, and described details of their wood structure ; Takahashi identified 3 distinct types of pollen including the one of Clavatipollenites from the Upper Cretaceous of Saghalien of Russia and, in addition, 8 distinct types of ephedroid pollen from the Lower Cretaceous of Hokkaido.On the other hand, Tobe and Oginuma both collected living materials of Ceratophyllum from various places in Japan to analyze its reproductive features and found 2n=78 and 2n=120 for the first time ; Ueda and Kosuge both analyzed a phylogeny of Ranunculaceae as one of representatives of primitive angiosperms on the basis of DNA sequences of glyceraldehyde-3-phosphate dehydrogenase(gap A), and discussed a possibility that is is comprised of multiple gene component.In these researches, we have accumulated many various information on evolutionary and morphological aspects of primitive angiosperms.