3o6 A NATURALIST IN THE GREAT LAKES REGION 



1 6. Ash-elm association Green heron association 



In steep-sided ponds this last may be replaced by the 



17. Swamp white oak association, which gives place to the oak forest 



(c) 



18. Floating sedge association 



19. Sphagnum-Cassandra association 



20. Tamarack association 



> Northern locust association 



2 1 . The flood-plain or elm-soft maple association 



This is subdivided into 



22. The bare river margin 



23. Ragweed-sunflower association 



24. Willow association 



25. Young ash-elm-maple association 



26. Mature elm-maple association 



Spotted sandpiper association 

 Plant bug association 

 Cecropia association 

 Yellow warbler association 

 Tanager association 



27. 



28. 

 29. 



30- 

 .SI- 



32. 



2>2>- 



34- 



The flood-plain association is stratified like the climax forest (which 

 see) and the several strata may be named as in the climax forest though 

 the constituent plants and animals will be somewhat dissimilar. 



Associations that Are Relatively Permanent, the Climax 

 OF Constructive Processes, Known as Climax 



Associations 

 They are: 



The prairie or Andropogon Jurcaius Meadow lark association 



association 



The oak-hickory association Green tiger association 



The beech-maple association Wood frog association 



Each of these is subdivided. In addition to the prairie grasses 



other plants are conspicuous, and several types of prairie may be 



distinguished in addition to the wet prairie (bobolink) and the A ndro- 



pogon furcatus (meadow lark) prairie. 



High prairie or Silphium association 



Very dry or Eryngiiim association 



Thin soil, rock bottom, prairie clover 



association 



The oak-hickory and beech-maple forests each have a 



Forest margin or Crategus association Brown thrasher association 

 Each is divisible into successive strata, much alike in the two except 

 for variations in the abundance of the constituent forms. 



The forest crown association Tree cricket association 



Jumping spider association 

 Leaf hopper association 



