242 OHIO XPEERIMENT STATION: BULLETIN 194. 



EXPLANATION OF PLATE XXI. 



Fig-. 1. An elm tree, Cleveland. Ohio, in bad condition, resnUinp- likelv 

 from g-as poisonirig-. 



Fig-: 2. An Ailanthus tree, Cincinnati, Ohio. The Ailanthus is a most 

 excellent tree for street planting- as it is almost immune from 

 insect attack and thrives even thoug-h the roots are completely 

 paved over as was the case of the tree illustrated. Smoke seems 

 to have little effect upon this species. 



