PLATE i6 



A.— A longitudinal section of a living apple root inoculated at X with mycelium of 

 Af. hypoxylon showing discoloration of wood and bark, after six weeks in a moist 

 chamber. 



B.— Surface view of a living apple limb inoculated with X. hypoxylon after five 

 weeks in moist chamber. 



C. — Black encrustation produced on an apple limb inoculated with X. hypoxylon 

 in a moist chamber. 



D. — An 8-day old colony of X. hypoxylonon starch agar showing characteristic zona- 

 tion and lobed margin. 



E. — A longitudinal section of a living apple root inoculated with Sphaeropsis malo- 

 rum, after four weeks in a moist chamber. A black mat of mycelium has formed over 

 point of inoculation. 



F.— A surface view of a living apple root inoculated with mycelium of X. hypoxylon, 

 after four weeks in moist chamber. 



