378 Journal of Agricultural Research voi. iv. no. 4* 



SUMMARY 



Wallrothiella arceuthobii, a fungous parasite on the false mistletoes of 

 conifers, is reported for the first time in the West. 



This fungus, first collected by Prof. Peck in New York and again by 

 Prof. Wheeler in the Upper Peninsula of Michigan, was considered a very 

 rare species until it was found to be of common occurrence in parts of 

 Montana and Idaho. 



Several new facts pertaining to the morphology and general behavior 

 of the fungus are established. 



Its host range has been greatly extended. 



The significant fact that the fungus is found in the West on those forms 

 of species of the same genus which are most similar to the eastern black- 

 spruce mistletoe, its host in the East, is thought to have some bearing 

 on the taxonomic position of this particular group of mistletoes. 



Its parasitism on the false mistletoes is found to be of great significance 

 in the control of these parasites, which are so destructive to many western 

 conifers. 



