262 A NEW APPLK TREE CANKER. 



a case where the stroma tends to be efifused ; while in i g it is 

 almost a ((uestion whether. a stroma is not absent altogether, the 

 pycnidiuni then being of Macrophoma type, with an outer dark 

 wall and an inner hyaline one. If this view be correct, then the 

 outer wall in the case of the stromate pycnidia is present, though 

 scarcely distinguishable from the inner layers of the stroma. 



Text fig. 3. 



It seems to me, however, ,more probable, considering the thick- 

 ness of the outer layer, that in i g the pycnidium is solitary but 

 stromatic. The pycnidia vary somewhat in shape ; i c shows 

 & case where the dividing wall between two pycnidia is absent, 

 though ostioles are distinct. Text fig". 2, which is a high-power 



