Abstract
1. Several morphologicai and physiological characters of triploid varieties were compared with diploids. 2. There was no clear difference on the leaf size and shape between triploids and diploids, but triploid leaves were thicker than those of diploids. As a rule every internal tissue of triploid leaves was thicker than diploids. It is evident that triploid leaves had larger stomatas of which the distribution density vias lower, compared with diploids. 3. No difference between both the plants could be recognized on the res.istance to brown blight total nitrogen and tannin content in suminer, the reduced form vitamin C content in winter, and regeneration power in cutting. Triploid varieties was more hardy to cold, and some of them had extremely early growing spring bud. The water reserving ability of triploid leaves isolated from stem was greater than that of diploids in September, but the relation changed to be indifferent. in December. 4. Generally triploid fertility was very low but the difference of fertility between each triploid variety was noticed. The pollen grains of triploids showed high sterility. 5. From progenies of triploids, we discovered one aneuploid plant (2n=44). The characters were same like those of triploids and the meio. sis was proceeded abnormally. 6. With colchicine treatment to the growing point of germinated seeds, some tetraploid plants (2ri=60) were obtained. At present, tetraploid plants are growing slowly and they have, dwarf form.
