482 



SPECIAL PLANT PATHOLOGY 



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Fig. 167. — Disease oi ash caused hy Fames {Poly porus)fraxinophilus. i. Cross- 

 section of ash wood; 2, of medullary ray; 3, medullary ray, showing later stage of 

 attack; 4, s. of wood cells; 6, starch grains from medullary ray cell; 7 diseased 

 wood; 8, transection from entirely rotted wood. (After von Schrenk, Hermann, 

 Bull. 32, U. S. Bureau of Plant Industry, 1903) 



