214 W. V. AGR. EXPERIMENT STATION [Bulletin 137 
dency to remain on the tree for some time. The burs on in- 
fected branches usually remain on the tree during the winter 
following its girdling. 
Diseased trees very frequently produce sprouts or “suck- 
ers” in considerable numbers. These may appear on the 
trunk or near the base of the tree. Such sprouts soon become 
infected, however, and very few survive more than. two or 
three years. 
Fic. 5.—Young tree showing postules on smooth bark, and sprouts. (See also 
Fig. 11, page 221.) 
A closer examination reveals the diseased band near the 
base of the affected portion. It is especially conspicuous on 
smooth bark, causing a reddish brown discoloration and pro- 
ducing numerous little pustules which break through the bark 
and set free vast numbers of spores. These spore masses are 
orange colored but vary considerably in appearance accord- 
ing to climatic conditions. During warm, moist weather they 
are especially prominent and sometimes may be seen as long, 
curly, yellow threads issuing from the pustule (figure 6). 
