352 BOTANICAL GAZETTE [APRIL 
The potato grown from the seed of the normal rest period treat- 
ment produced plants of several stalks. Judging from the investi- 
gations (1, 7) already referred to, one would expect that in these 
tubers the products of chemical reactions had approached a certain 
equilibrium, so that the sugar formation was at its maximum, and 
conditions were optimum for the activity of the diastatic enzymes. 
The potatoes planted without rest period treatment could not 
undergo similar changes as those of the normal rest period ones, 
as the agency of vegetative growth induced by the peculiar condi- 
tion under which the tubers were placed would preclude the attain- 
ment of a similar chemical equilibrium as that existing in the 
tubers of the normal resting period treatment. 
That not all of the food material in the seed tubers was used in 
the growth of the plants was shown by the fact that the seed potato, 
when planted again, germinated, grew, and matured a crop. In the 
second growth of the tuber several stalk plants appeared above 
ground in about the normal time. Excepting the fact that the 
second planting was not carried out with a sufficient number of 
plants for conclusive results, the results obtained indicated that the 
after-ripening of the potato, while it grew a crop, did not serve to 
decrease materially the growing period of the plant for its second 
growth. 
With a more detailed study of the potato by means of the 
analyses of the seed tubers before and after their plant production, 
some data may be obtained which may throw light upon this 
interesting phase of plant physiology. 
Summary 
1. A study of the effect of various rest periods of the potato 
tuber upon the subsequent growth of the plants is here 
reported. 
2. After-ripening processes in the potato occurred whether the 
tubers were in the ground or in ordinary storage. 
3. Potatoes planted immediately after the inaturaticnl of a crop 
required a much longer period for the germination of the buds 
and the appearance of the plants above ground than did potatoes 
that had a rest period. 
