222 



BULLETIN 193. 



branches, but was unable to form the fruit bodies until the larger 

 limbs were pruned. 



Several of the branches of this apple, bearing fruit bodies, 

 were taken for examination. The character of the heart rot is 

 in all essential respects the same as that observed in the maple 

 and beech. 



POLYPORUS PINICOLA. 



The pine destroying polyporus is widely distributed in the 

 United States and other north temperate regions. It occurs on 



81. Section of fruit body of Polyporus pinicola, shozving strata of tubes. 



various conifers, on the pines, spruces, balsams, larches, etc. 



The fruit bodies are shelving, hard and firm, though not so 

 hard as those of Polyporus igniarius. They are perennial and 

 therefore single specimens increase in size from year to year, 

 usually becoming broader below and of course thicker from each 

 annual accretion layer. 



The fruit body is marked on the upper surface by prominent 

 concentric ridges and furrows. The marginal ridge is the one 

 representing the latest year's growth The color of the fruit 

 body is from dark brown to nearly black at the base, varying to 

 a reddish brown near the margin. The marginal zone represent- 



