Bui. 212, U. S. Dept. of Agricultur 
Plate I. 
Mm 
Fig. 1.— A 6-Year-0ld Jack Pine In- 
fected with Peridermium Cerebrum. 
The complete girdling of the main stem by 
two oppositely arranged galls is shown. 
Note the wedge-shaped gall tissues. 
Fiq. 2.— Four-Year-Old Seedlings 
of Jack Pine, Showing the Char- 
acteristic Swellings of Perider- 
mium Cerebrum. 
The entire crown of the seedlings develops 
into spherical brooms. 
Fig. 3.— Various Types of Infection of Young Jack Pine by Peri- 
dermium Comptoniae. 
Note that in the central figure the fungus has invaded the underground tissues 
of the stem. 
