PLATE 88 
A. —Irish Cobbler potato plants grown in soil held at constant temperatures of 
i8° and 27 0 C. The effect of the higher temperature is shown in the smaller size 
and increased number of leaves, the shorter intemodes, and the decreased diameter 
of the stem. Comparative figures are given in Table IX. 
B. —Series of Irish Cobbler potato plants grown in soil held at soil temperatures of 
9 0 , 12 0 , 15 0 , 18 0 , 21 0 , 24 0 , 27 0 , and 30°. Plants in A were taken from a different 
but parallel series. Plants 46 days old. 
