244 BOTANICAL GAZETTE [APRIL 
Pot 31. In light; two shoots (from a whole potato), 200 and 190™™ high, with 
large leaves. 
Pot 32. In darkness; three shoots (from a whole potato), 150, 150, I ae 
high, with large leaves. 
These plants were left under these conditions from May 15 to 24, and no 
intumescences were formed. The temperature of the air in the bell jars was 
about 73°F., and of the soil 55° F. 
EXPERIMENT XII 
Four plants were placed in the shade, with their roots kept cold. 
The temperature of the roots averaged 56° F., and of the air above 
73°F 
Pot 33. One shoot (from a cut potato), 135™™ high, with rather large leaves. 
Pot 34. One shoot (from a cut potato), 1oo™™ high, with large leaves. 
Pot 35. Three shoots (from a whole potato), 135, 100, 115™™ high, with large 
leaves. 
Pot 36. Two shoots (from a cut potato), 210 and 160™™ high, with large 
leaves. 
These plants were allowed to remain eleven days under these conditions and 
no intumescences were formed. Some of the leaves became yellow. 
EXPERIMENT XIII 
Four plants were placed in the shade, with their roots kept warm 
from the warm water pipes. The temperature of the air in the bell 
jars averaged about 84° F. 
Pot 37. One shoot (from a whole potato), 170™™ high, with large leaves. 
Pot 38. Two shoots (from a cut potato), 120 and 100o™™ high, with large 
ves, 
Pot 39. Two shoots (from a cut potato), both 130™™ high, with large leaves. 
Pot 40. Three shoots (from a cut potato), 175, 150, 100™™ high, with large 
leaves. 
In four to five days intumescences had formed in very great numbers over all 
four of these plants. 
On May 25, shoots which had come up a third time from the 
same lot of potatoes were covered with bell jars. 
EXPERIMENT XIV 
Two pots were placed in sunlight. 
Pot 41. One shoot, 150™™ high, with large leaves. 
Pot 42. One shoot, 200"™ high, with a slender stalk and small leaves. 
In seven days no intumescences were formed. 
