植物相からみた日本の中期更新世

Abstract

Stratigraphic changes of fossil assemblages of macroscopic plant fragments and pollen during the middle Pleistocene in Southwest Japan are briefly enumerated as follows.1. Most of relict elements of the Pliocene flora as Metasequoia, Glyptostrobus, Juglans megacinerea, Liquidambar etc. already disappeared during the early Pleistocene. But some species as Cunninghamia lanceolata, Picea koribai, Ilex cornuta and Paliurus nipponicus still remained, and they disappeared during the middle Pleistocene.2. There is a large possibility that Liquidambar revived temporally its distribution in the southern coastal region of Southwest Japan during an interglacial age in the middle Pleistocene.3. Such northern elements as Larix gmelini, Abies veitchii, Picea jezoensis var. hondoensis, Oxycoccus palustris etc. have their first appearance during a glacial age in the middle Pleistocene.4. The specialization of Larix leptolepis, one of the endemic species of Japan, may have occurred during the middle Pleistocene in age. And its ancestral species may be L. gmelini inferring from their present ecological and phytogeographical relations.