COMMUNITIES 41 
¢) Hyaliodes vitripennis, or black-oak, red-oak association of the sand 
and other sterile soil series 
d) Cicindela sexguttata, or red-oak, hickory association (climax, or final 
forest association of the savanna climate) 
e) Wood-frog or beech-maple association (the climax or final associa- 
tion of the forest climate) 
The evidence for the relations of the different formations and 
associations here suggested is presented from time to time in the following 
pages, and on the basis of this, is graphically represented in Diagram 9, 
on p. 312, where both physiological and genetic relations are indicated. 
