PLATE LV 



Fig. I. — Razoumofskya douglasii on Pseudotsuga taxifolia, infected with Wallrothiella 

 arceuthobii. Note that two capsules escaped infection. Natural size. 



Fig. 2. — R. douglasii, var. abieiina, on Abies grandis, infected with W. arcetithobii. 

 Natural size. 



Fig. 3. — R. douglasii, var. abieiina, on Abies lasiocarpa, infected with W. arceuthobii. 

 Natural size. 



Fig. 4. — R. douglasii, var. microcarpa, on Picea engelmanni, infected with W. 

 arceuthobii. Natural size. 



Fig. 5. — Left and right figures showing infection of R. americana with W. arceuthobii 

 by infected plants of R. douglasii. The plants at lower part of figures are normal and 

 fully mature. The middle figure shows infection of R. americana by spraying upon 

 the plants a mixture containing spores of W. arceuthobii. Natural size. 



