Abstract
In the Kinu Bog situated at the altitude of 2,000 m and in the belt of conifers, birch pollen occurs almost exclusively (93%) at the bottom. It is likely that this shows clearly the initiation of forestation due to the climatic amelioration during the Allerod oscillation in the Late-glacial period. In contrast to it, in the nearby Oze Bog 600 m below and in the belt of deciduous trees, NAKAMURA (1951) counted much the same amount of coniferous pollen as of birch pollen at the bottom. This coniferous pollen had probably been derived from the woodland beneath, because this country has been almost entirely free from glaciation. The distance between bladders as measured on the ventral side is more than 20μ in about 75 per cent of Abies pollen, while none of Picea pollen exceeds 20μ. Consequently, Abies (%)=x/75×100 : x being the percentage of those over 20μ distant. The vast majority of Abies pollen show a conspicuous constriction at the roots of their roundish bladders. Picea pollen is characterized by a flattening of the bladders normally, but frequently resembles Abies pollen in the shape of the bladders.
