"X^vo 



Bulletin 



OF THE 



Illinois State Laboratory 



ov 



Natural History 



Urbana, Illinois, U. S. A. 



STEPHEN A. FORBES, Ph.D., L.L.D., 

 Director 



Vol. XIL September, 1915 Article I. 



THE RELATION OF EVAPORATION AND SOIL MOISTURE 

 TO PLANT SUCCESSION IN A RAVINE 



BY 



Fred Theodore Ullrich 



