Betula ovalifolia is a shrubby birch counted as one of the relicts of the Last Glacial Age in Japan. To elucidate the history of this species in the Nishibetsu Mire, Betsukai in eastern Hokkaido, we studied the pollen morphology of !ve Betula species native to Hokkaido and the temporal distribution of B. ovalifolia type pollen in the mire sediments. Measurement of the equatorial length (E), ectopore length (EP), and pore depth (PD) of modern pollen grains revealed that pollen grains of B. ovalifolia occasionally have clearly larger E/EP or E/PD than those of the other Betula species. In the sediments collected by hand boring in the Nishibetsu Mire that dated back to ca. 6500 cal BP according to radiocarbon dating and correlation of tephra layers, Betula pollen accounted for 4–34% of the total arboreal pollen with 7–50% of them having larger E/EP that characterizes B. ovalifolia pollen. This result indicated that B. ovalifolia has probably been dominant in the mire vegetation since ca. 6500 cal BP.

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We describe plant macrofossils that comprise the collection made by Dr. Sigeru Miki at the Tado site, Mie Prefecture, central Japan, and stored in the Osaka Museum of Natural History. The specimens were dated to two age spans, 40,300–39,070 and 21,920–20,270 cal BP, corresponding to marine isotopic stage 3 (MIS 3) and the later stage of the last glacial maximum (LGM), respectively. Macrofossils from the LGM bed were dominated by temperate conifers such as Tsuga sieboldii, Picea sect. Picea, Larix kaempferi, and Chamaecyparis obtusa and also included diverse temperate broadleaf trees such as Cercidiphyllum japonicum, Pterocarya rhoifolia, Fagus japonica, and Ostrya japonica. Results of the pollen analysis of sediments adhered to a Tsuga cone indicated an expansion of the temperate coniferous forest around mixed coniferous and deciduous broadleaf forests that had developed along the Tado River. Occurrence of subalpine conifers at this site indicated the distribution of subalpine forests in the montane zone, contiguous with the mixed coniferous and deciduous broadleaf forest. Inland areas around the Tado site located mid-way between the coasts of the Paci!c Ocean and Japan Sea were assumed to be refugia for temperate trees during the LGM when pinaceous conifers prevailed in cenral Japan. This study showed that reinvestigation of museum collections is important to reconstruct the distribution of paleovegetation during the last glacial stage.

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During excavations in 1984 and 1985 of the Ikiriki site, a lowland wetland site in Nagasaki Prefecture, stones of a peach (Prunus persica) was excavated from a cultural layer containing artifacts of the early Jomon period. Because peach is an exotic cultigen native to China, these stones were thought to be the oldest record of peach in Japan. Radiocarbon dating for 11 samples of these peach stones and related plant remains showed that these peach stones were mainly of the middle to late Yayoi period, indicating that the later peach stones seem to have fallen into the cultural layers of the early Jomon period.

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