The results of investigation on the natural distribution of Camellia sasanqua(an endemic tree of Japan), are shown in figure 2. The northern limit of its natural distribution is Ikinoshima Isl. (about 33°15′N.L.)in Nagasaki prefecture and its southern limit is Yakushima Isl.(30°15′N.L.)in Kagoshima prefecture. The fact that sasanqua is not found in the southern regions beyond Yakushima Isl. seems to be attributable to the geohistorical causes. In southern Kyosho, it thrives so densely that it often appears as the dominant-species of forest communities 300-600m high above sea level, especially in the Distylium racemosum forests. And it occurs rarely in such Abies firma forests as 900m high above the sea level. In the islands or peninsula of north-eastern Kyushu surrounded by warm currents, it is found comparatively abundantly. Generally speaking, sasanqua is more abundant on mountain sides where the soil is well drained, more so in the third stratum than in the second of the forests ; it is little in forests along ravines. It general it seems that the trees are thinly scattered in the districts near the northern limit habitate. As the climatic factor, "The index of warmth"of northern habitats was recognized as 130°-135°. Therefore, it may be said that this tree is closely related to the subtropical trees from"The index of warmth".