232 ILLINOIS ACADEMY OF SCIENCE 



was found only in mesophytic habitats. While Corylus 

 americana was found growing with Hamamelis virginiana 

 in mesophytic associations, in the main, it was found in 

 less mesophytic situations. 



LITERATURE CITATIONS. 



1. Atwood, W. W., and Gold th wait, J. W., Physical geography of the 

 Evanston-Waukegan region. Bull. 7, State Geol. Sur. 111. 



2. Cowles, H. C. The plant societies of Chicago and vicinity. Geog. 

 Soc. Chicago, Bull. No. 2. 1901. 



3. Cribbs, J. E., Plant associations of western Pennsylvania. Chicago. 

 1916. 



4. Salisbury, R. D., and Alden, W. C, The geography of Chicago and 

 its environs. Geog. Soc. Chicago. Bull. No. 1. 1901. 



5. SherfE, E. E., The vegetation of Skokie Marsh, with special refer- 

 ence to subterranean organs and their interrelationships. Bot. Gaz. 

 53 : 415-435. No. 5. 1912. 



Vegetation of Skokie Marsh. Bull. 111. State Lab. Nat. Hist. 

 9 :575-613. 1913. 



6. Ullrich, F. T., The relation of evaporation and soil moisture to 

 plant succession in a ravine. Bull. 111. State Lab. Nat. Hist. 12 : 



1-16. 1915. 



Acknowledgements. 



The writer wishes to express her appreciation to Dr. 

 Henry C. Cowles, for the direction in the technique of 

 ecological surveying, the identication of certain plants in 

 their winter condition, and for the use of Figs. 7, 12, and 15, 

 which were taken in the vicinity of Glencoe in 1900, and are 

 used as' comparative studies in this paper ; also to Paul S. 

 Sedgewick for taking the remaining photographs with 

 which this paper is illustrated. Grateful appreciation is 

 likewise extended to Dr. Fuller, of the University of Chi- 

 cago, for many helpful suggestions. 



Acknowledgment is due Mr. William Turnbull, and 

 Mr. Frederick De Lang for information regarding pioneer 

 forests ; and Mr. Frank Englehardt for providing and sug- 

 gesting maps; also to other citizens of Glencoe who con- 

 tributed information of value concerning the early forests. 



LEGENDS. 



Fig. 1. A section of land (640 acres). Numbers indicate 10 acre 

 plots, letters 40 acre plots of land, or "forties." 



Fig. 2. Portion of New Trier Township. Numbers in the figure indi- 

 cate the sections surveyed. 



Fig. 3. Hydro-mesophytic association in which Fraximus nigra and 

 Quercus bicolor form the innermost tree zone about the pond 

 (N. T. 1, 17). Cephalanthus ocddentalis is the shrub grow- 

 ing in the water. 



