1. Studies on shape, process of growth and germinating character have been studied. 2. Close correlation of+0.604 has been found to exist between vertical diameter and weight of tuber. This correlation tendency is obviously observed in its early stage of growth. The growth in its vertical diameter, the rate of which decreases gradually, stops when the tuber becomes about 100 grams in its weight. 3. Correlation of+0.191 exists between the horizontal diameter and the weight of tuber. The above relation is observed not to be very close. Its horizontal dia almost finishes its growth before it becomes 50 grams in weight. 4. The knots of tuber increase in number as the tuber becomes larger, but there exists a certain limit to the extension of intervals between knots. Whether the vertical dia grows well or not, depends upon how many knots increase in number. 5. Close correlation of+0.78 exists between the increase of weight in the process of secondary growth and the weight of tuber. Particularly, the growth in latter term takes effect chiefly in the course of secondary growth. 6. The vertical section of tuber can be shown by the Equation of Circle stated below: b(x2+y2)+(a2-b2)y=a2b From the above Equation, surface area and cubic volume of tuber can be calculated. 7. At the beginning period when the formation of tuber takes place, no difference is observed between the growth of back side of tuber and that of front side. But as the time passes, the growth of front side falls behind. 8. The shape of vertical section of small tuber is nearly perfect circle, and it becomes spindle shaped as the tuber grows larger. 9. Immediately after the dormant period, tuber has generally the character of apical dominance, but the number of germinating tubers varies as the time elapses. As to the part grown in the course of secondary growth, the polarity becomes independent of its original tuber when it grows to some extent and germination takes place with that of apical germ.
