No. 468.] AMERICAN FOREST CENTERS. 881 
distinct societies occupying the same or similar habitats. For 
example, in southern Michigan, the xerophilous bog societies 
and the hydrophilous swamp societies are so related. The 
former, however, are a part of the Northeastern Conifer forest, 
while the latter belong to the Deciduous forest succession. Con- 
sequently, where the bog societies are surrounded by oaks they 



à d. | 3 pe AM D 
- um S . 
agnolia 
f » lauc 
Populus 
uf 4 ET heterophylla 
r h te & E t 
> Myssa 
ze me : aquatica 
7 
rd 
Magnolia foetida 
S Ai: 4s Populus heterophylla 
: Nyssa aquatica 
Magnolia glauca $e 7 A) 
Magnolia foetida ` 
$ o 
Q.Texana D b 
4 


+h as 

= + fxh. th + Conife: 
IG. &. a p p ere g pt Conife 
a center. Magnolia glauca, M. fætida, Nyssa aquatica, Populus heterophylla, Taxo- 
dium distichum, and Quercus texana. 
bear no successional relationship, while the swamp societies 
change gradually into the oak and climax stages of the Decidu- 
ous forest. In such cases the geographic considerations are of 
equal importance with the physiographic, for the proper classifi- 
cation of the plant societies. 
Turning to the coastal plain of the southeastern states, we 
find a dominant forest of Conifers, with mixed Conifer ; and 
broad-leafed societies on the low grounds. Here slight differ- 
