7i6 



Journal of Agricultural Research 



Vol. XII, No. ir 



(Engelm.) Piper] and were the source of infection of the reproduction. 

 The young trees were well distributed over the area and were dominant. 

 The results of this study are summarized in Table I and demonstrate 

 very clearly the damage which may result from attack by this parasite 

 on yellow pine. 



Table I. — Effect of mistletoe on yellow pine 



Age of tree. 



Basis No. 



Infected. 



Years. 



4 ' 8 



5 lo 



6 14 



7 ! 9 



8 j 19 



9 1 10 



10 1 7 



I 



Total 77 



Unin- 

 fected. 



50 

 27 



42 



35 

 20 



23 

 16 



213 



Average height of trees. 



Infected. 



Cm. 



15. 22 

 22. 84 



35-53 

 48. 22 



53-29 

 63-45 

 73.60 



44,72 



Uninfected. 



Cm 



25 



35' 

 50' 

 71 

 78. 



93 

 109 



■38 

 •53 

 .76 

 .06 

 .68 

 .90 

 - 13 



57-87 



DiEference in 



height be- 

 tween infect- 

 ed and un- 

 infected 

 trees. 



Cm.. 

 10. 15 

 12. 69 

 15.22 

 22. 84 

 25-38 

 30-45 

 35- 53 



13-15 



During the above study it was plainly observed that the length of the 

 intemodes of the infected trees, also the length of the terminal and lateral 

 buds of the main shoot, were much shorter than those of the uninfected, 

 and led to the following study on Douglas fir {Pseudotsuga taxijolia) in 

 the Missoula River region near Missoula, Mont. The trees were infected 

 with Razoumofskya douglasii Engelm. For this study trees were selected 

 over an area without recourse to sample plots. The only point adhered 

 to was the selection of trees on same type of site, condition of growth, 

 and an average age of 18 years. The results are given in Table II 



Table II. — Effect of mistletoe on Douglas fir 



The foregoing results clearly demonstrate the eflFect of the formation 

 of brooms and burls on the storage of food materials in the terminal buds 

 and shoots. It is a well-known fact that in the terminal bud are stored 



