192 ILLINOIS STATE ACADEMY OF SQENCE 



ciency." "Agriculture is neither more nor less than ap- 

 plied plant and animal ecology." Although the present in- 

 vestigation has been one wholly separate from all economic 

 questions, being one entirely in pure plant ecology, it is evi- 

 dent that in the near future many similar investigations 

 will need to be undertaken in the field of applied plant 

 ecology. 



REFERENCES 

 Bradfield, Wesley. 



Typical Forest Regions in Illinois. 



A Report Based on Preliminary Examinations. 

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Eikenberry, W. L. 



Some Notes on the Forests of Ogle County. 

 Trans. 111. Acad. Sci., Feb. 1912. 



HaU, R. C. and Ingall, 0. D. 



Forest Conditions in Illinois. 



Bui. 111. State Lab. Nat. Histy., vol. 9, art. 4, 1911. 



Kauffman, H. G. and R. H. 



Historical Encyclopedia of Illinois and History of Ogle County. 

 2 vols., Chicago, 1909. 



Kincer, J. B. 



Seasonal Distribution of Precipitation and Its Frequency and Intensity 

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 Month. Wea. Rev. 47:624-33, 1919. 



Leverett, F. 



The Illinois Glacial Lobe. 

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Pool, R. J. 



The Invasion of a Planted Prairie Grove. 

 Proc. Soc. Am. For. 10:1-6, 1915. 



Salisbury, R. D. and Barrows, H. H. 



The Environment of Camp Grant. 

 111. State Geol. Surv. Bui. 39, 1918. 



Schwarz, G. F. 



The Diminished Flow of the Rock River in Wisconsin and Illinois. 

 U. S. Dept. Agric. Bur. of Forestry, Bui. 44, 1903. 



Shreve, F. 



A Map of the Vegetation of the United States. 

 Geog. Rev., 3:119-25, 1917. 



Transeau, E. N. 



Forest Centers of Eastern America. 

 Am. Nat. 39:875-89, 1905. 



Waller, A. E. 



Crop Centers of the United States. 



Jour. Am. Soc. Agron. 10:49-83, 1918. 



Ward, R. deC. 



Rev. Kincer, J. B. Month. Wea. Rev. 47:631-2, 1919 art. in Scien. 

 Month. 9:210-23, 1919. 



