日本列島北限「カラマツ」球果の変異とその古植物学的意味

概要

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“Japanese Larch”found in the northern reaches of the Japanese Archipelago are 150km from their major area of distribution; being isolated, they are on the verge of extinction.During two surveys conducted in 1985 and 1986, twelve“Japanese Larches”were confirmed to be growing on Mt. Manokami-dake near Mt. Zao. When compared with those from Japanese Larch in central Japan, the cones of the northern “Japanese Larch”were characteristically smaller and had fewer scales, and the scale was reflexed hardly at all at the apex. These morphological characteristics are similar to those of the Olga Bay Larch (Larix olgensis) and are intermadiate between the Japanese Larch (Larix kaempferi) and the Kurile Larch (Larix gmelinii).A large quantity of remains of the Kurile Larch-which is known to have existed in the last glacial age-was discovered in paleolithic sites from Tomisawa, Sendai, near Mt. Manokami-dake recently. This finding suggests that it had overlapping ranges with the Japanese Larch, and that the “Japanese Larch”on Mt. Manokami-lake might be a taxon that arose from interbreeding between Japanese Larch and Kurile Larch in the last glacial age or an independent taxon, similar to the Olga Bay Larch, which has remained as a relict.
日本第四紀学会の論文