288 Journal of Agricultural Research voi. vi. xo. s 



cutting. The brooms never produce cones and the normal parts of the 

 supporting branch are usually sterile. The branches bearing patches of 

 infected needles or brooms should be piled and burned' as soon as possible. 

 This may be done in the course of the regular brush-piling operations. 

 If young trees below the regulation cutting diameter are so badly 

 "broomed" that in the opinion of the forest officer the increment of 

 the tree will be seriously impaired, and whenever the cost is not prohibi- 

 tive, such trees should be lopped and immediately burned. The chief 

 reason for such procedure is to protect the reproduction from infection, 

 thus insuring a healthier forest in the future. 



PLATE XXXII 



Fig. I. — Needles of Pinus ponderosa infected with Hypoderma deformans, showing 

 the apothecia. Natural size. 



Fig. 2. — Branches of Pinus ponderosa deformed and broomed by Hypoderma defor- 

 mans. 



Fig. 3. — A branch of Pinus ponderosa, showing how it will hang vertically when 

 supporting a large broom caused by Hypoderma deformxins. 



