198 



CLASSIFICATION OF PLANT COMMUNITIES 



The third type of society is represented by cryptogamic societies. 

 These, again, are often seasonal and so might be called aspect 

 societies, and they are also layer societies. They are sufficiently 

 distinct, however, to merit separate classification. The subdomi- 

 nants are usually mosses, liverworts, lichens, or, sometimes, fungi. 

 Cryptogamic societies are often very difficult to distinguish from the 

 colonies discussed in Paragraph 126. 



Fig. 86. — A bottomland forest associes in southern Illinois. 



Societies are usually smaller and of a lower morphological rank 

 than consociations, but a society is not a part of a consociation in the 

 sense that the consociation is a part of the association. It is rather 

 a part of the association, just as the consociation is, and a single 

 society may extend over portions of more than one consociation. 



126. Climax and Serai Communities.— The fully mature plant 

 associations of any climatic region represent the most mesic vegeta- 

 tion that can be supported by the climate of that region. For this 

 reason the mature communities are called climax associations. 

 Often the majority of the communities in any region are not climax 

 but represent one or another of the developmental stages of the 

 climax communities. These may be called serai communities from 

 the series of stages that lead from bare area to climax. 



Most ecologists prefer to use two distinctive sets of terms when 

 dealing with climax and serai communities. Thus the terms associa- 

 tion, consociation, faciation, and society are applied only to climax 

 communities while corresponding terms with different endings, 

 namely, associes, consocies, facies, and socies are applied to serai 



