74 



EVERGREENS OF COLORADO 



Fig. 58. Common Ailments of Evergreen Trees, a. Douglas Fir 

 and Blue Spruce affected by a plant louse, x l / 2 . b. Red Cedar, showing- 

 galls caused by fungous parasite, x ?-,. c. Witches broom of Lodgepole 

 Pine caused by a mistletoe, x%. d. A mistletoe on Yellow Pine. 



