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four conspicuous members, namely, Acer ruhrum, Quercus alba, 

 Fagus grandijolia, and Castanea dentata. There are additional 

 species always present; some of which are more mesophytic 

 than these; and in such instances they are usually forms typical 

 of the moister depressions such as Tsuga, Tilia, Fraxinus, Mag- 

 nolia, Liriodendron, and Pinus. Other components of the forest 

 with a lower degree of mesophytism include Carya ovata, Carya 

 alba, Carya glabra, Quercus imbricaria, Quercus rubra, Cornus 

 florida, Osirya virginiana, Prunus serotina, Carpinus caroliniana, 

 etc. 



Fig. 7. The white-pine — hemlock stage, which follows the Tsuga formation. 

 A pure stand of conifers which will ultimately be replaced by Acer ruhrum, Mag- 

 nolia acuminata, and Fagus grandifolia as indicated by the undergrowth. 



Of the four dominant tree members, Fagus, Quercus, Casta- 

 nea, and Acer, the last two are found as components in the 

 flora in almost all situations developed on morainic topography. 

 The beech is more mesophytic, and has a tendency to avoid the 

 dry exposed slopes; assuming rather a position with more favor- 

 able moisture relations such as is afforded upon the rolling upland 

 or upon the moist slopes of valleys. The white oak is least 

 mesophytic of these and develops in purest stands upon the 

 higher slopes where the water conditions are less favorable for 



