3io 



SAND RIDGE 



Cottonwood 

 Gray pine 

 Black oak 



White oak 



ECOLOGY 



CLAY BLUFF 



Aspen 

 Cottonwood 

 Hop-Hornbeam 

 White oak 



Red oak Red oak 



Hickory Hickory 



BEECH AND SUGAR MAPLE 



Tulip Hickory 



Basswood Red oak 



White elm and 

 White ash 



Swamp white oak 

 Buttonbush 

 Cattail and Bulrush 



Water-lily and Water 

 Mill-foil 



Bur oak 



Basswood 

 Hawthorn 



Slippery elm and 

 White elm 



Chara 



POND 



River maple 

 Black willow 

 FLOOD-PLAIN 



Diagram 8. — Showing the convergence of four types of habitat, to the beech 

 and maple forest. Read from the extremities toward center. (Prepared with the 

 assistance of Dr. Cowles and from his writings.) 



