340 - BOTANICAL GAZETTE [APRIL 
In the light of the investigations above mentioned the present 
experiment was undertaken to ascertain whether any vegetative 
changes in form would develop in the plants grown from tubers of 
different rest period duration, and to what extent correlation, if 
any, could be drawn from changes in the chemical composition of 
the tubers during the rest period. The experiment was carried out 
in the greenhouse. Due precautions were observed in order to attain 
uniform and comparable conditions of moisture, temperature, and 
culture throughout the length of the experiment. Plantings were 
made at different seasons of the year to eliminate as much as pos- 
sible the influence of the variation of climate. The potatoes were 
planted and grown to maturity in large earthen pots containing 
12 K. of a good loam soil. New soil was used for every planting 
and the tubers were planted to a depth of 3 inches unless other- 
wise indicated. The harvest of the crop at maturity was at the 
time when the leaves began to dry and fall, while the water content 
of the soil was still at optimum condition. As the tables indicate, 
tubers of various rest period durations were used. Plants were 
grown from tubers of a continuous no-rest period treatment of 
several generations, as well as from those of rest period treatment 
also of several generations. The results obtained are indicated 
in the tables. 
A potato known as the Salinas Burbank was used as the original 
seed for the experiment. It was cut into two nearly equal parts 
of 150 gm. weight, and planted. Periods of 10 and 11 days respec- 
tively were required for the plants to appear from these two half 
tubers. Three stalks were produced from one half tuber and four 
stalks from the other. Rapid growth and strong stalk production 
characterized these plants. Maturation occurred for the duplicate 
plants in 86 and go days respectively from the time of planting, 
while the actual growing period from the day of appearance of the 
plants above ground to the harvest averaged 77.5 days. 
Series IT were the plants produced from seed taken from the 
crop of series I and were planted immediately after harvest. In 
this series the potatoes planted were whole tubers of approximately 
roo gm. each. Periods of 62 and 67 days were required for the 
seedlings to appear in the duplicate pots. In this series one-stalked 
