Abstract
Among the reforested trees. Pinus densiflora SIEB. et ZUCC. and P. thunbergii PARL. are the important ones in Japan. Many taxonomic studies have been made on the hybrids between both species, which are called "Akakuromatsu" Pinus densi-thunbergii UYEKI. Hitherto, it has been illustrated that the efflcient taxonomic Indicators were some anatomical characteristics In the needles, for examle, the position of resin canal and the amount of hypodermal cells. However, these classifications were carried. out on the natural hybrids, so they had been used without recognizing the genetical systems of the indicators. Therefore, If some specific genetical systems such as dominant or maternal. effect exist in the indicators, the classification may be inadequate and erroneous. Moreover, if the number of the indicators are a few, the classification will be often devoid of objectiveness. The present study was schemed to examine these problems.
