Studies in Prairie and Woodland 5 



lands along Salt creek at Lincoln. This fact serves to intensify 

 the floral contrast all the more as we compare the two areas in- 

 cluded in these studies. 



Besides the common oaks and hickories the following are 

 among the more conspicuous ligneous species absent from the 

 Lincoln woodlands : Ainelanchier canadensis, Aesculus glabra, 

 Asiniina triloba, Cercis canadensis, Crataegus mollis, Prunus sero- 



FiGURE 2. The location of the sumac station at Lincoln. 



tina, Tilia americana, Ostrya virginiana, Xanthoxylum amer- 

 icaniim and Corylus americana. The absence of such species as 

 these means that the wood}^ plants that have succeeded in invad- 

 ing this more xerophilous area have assumed a more decidedly 

 dominant rank than is the regular feature of their distribution in 

 the woodlands along the Missouri. Hence Quercus macrocarpa, 

 Fraxiniis pcnnsylvanica, Ulmiis fulva, Celtis occidentalis, Acer 

 negundo, Acer saccharinum, and Juglans nigra have become the 

 decidedly dominant forms along Salt Creek. Associated with 

 these trees are the infrequent and unusually widely scattered 



II 



