7. 



Fio 



Uimus 



PLATE III. 



Fig. 7. Cross sections of an Ulmus (American elm) growing on the campus 

 at State College, Pennsylvania, showing wide and rather uniform rings. Here 

 the conditions for growth are favorable. 



Fig. 8. Cross sections of an Ulmus (American elm) growing on the hillside 

 at Nine Mile Run across the river from the mills at Homestead. Shows a de- 

 cided irregularity in the character of the annual rings. 



