242 2 . OHIO XPEERIMENT STAlTION: BULLETIN 194. 



EXPLANATION OF PLATE XXI. 



Fig. 1. An elm tree, C.'eveland. Ohio, in bad condition, resultinp- likply 

 from gas poisoning-. 



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

 excellent tree for street planting as it is almost immune from 

 insect attaclc and thrives even though the roots are completely 

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

 to have little effect upon this species. 



