Abstract
1. It was shown that, in the early planting, the varietal difference as to the period required for initiation of flower bud was clear, while was carcely recognized in the late planting. 2. As to the days for flowering, a similar trend was also shown, but was not so remarkable as obtained in the former case. 3. Concluding from the variations of external character which indicate the intensity of thermal response, the varieties of tobacco plants, so far as this investigation is concerned, were classified into 3 groups (B, Y, X, ) and out of them the Group B was observed to be most sensitive to abnormal acceleration.
