cp:phalosporium wilt of elms 



13 



The spore heads are borne on short conidiophores from which the spores are 

 abstricted at the tip. These spores cling together to form a head. As few as 

 one or two spores to a head were observed in some cases, while most heads con- 

 tained many spores. Some heads were highly refractive because of the large 

 quantity of mucus. A very few conidiophores were observed which had more 

 than one head, forming a chain of several spore heads. 



Figure 8. Mycelium Growing in Van Tieghem Cell, showing spore heads and anastomosing 

 hyphae. (x 1000) 



Methods of Inoculation with Host Reactions 



For use in inoculations a culture of the fungus, as nearly typical as could be 

 found, was selected. This culture had been obtained from twigs which had been 

 sent to the laboratory from the town of Northbridge. The twigs had been col- 

 lected by Achod Ahmadgean, July 23, 1935, from a tree situated on the East 

 Douglas Road near the town line. The tree was described as being approximately 

 twenty-five feet high and at that time not seriously afTected by the disease. 



