24 



The study of the vegetation of the sand deposits of Ilhnois is 

 therefore of especial scientific interest because they constitute the 

 only considerable area of natural vegetation in the state, and because 

 their vegetation is closely related to that of the original prairie. It 

 is also of some general value, since it concerns an area which has re- 

 ceived little attention from botanists, and because it affords intel- 

 ligible illustrations of certain ecological principles. 



The field work upon which the present paper is based was done 

 during the summer of 1908. Reference is also frequently made to 

 the field work at Havana in August, 1903, and August, 1904, the re- 

 sults of which have already been published (Hart and Gleason, 1907). 

 The itinerary during 1908 was as follows: 



May 28, 29, St. Anne, Kankal<:ee county. 



May 3 1 -June 3, June 12-24, August 15-18, Hanover, Jo Da- 

 viess county. 



June 25-29, Shirland, Winnebago county. 



June 30-July 3, August 19, 20, Dixon, Lee county. 



July 4-15, August 10-14, Oquawka, Henderson county. 



July 16, Forest City, Mason county. 



August 7, Topeka, Mason county. 



August 8, Havana, Mason county. 



August 21, Amboy, Lee county. 



From June 12 to 19 Mr. Frank C. Gates assisted in the field 

 work. He also identified many of the plants mentioned in the paper. 

 The grasses and sedges were identified through the courtesy of Mrs. 

 Agnes Chase. Mr. H. N. Patterson rendered important assistance in 

 the field work in the Oquawka area. Dr. H. S. Pepoon has supplied 

 valuable information concerning the Hanover area. To each of 

 these the writer extends his thanks for their interest and appreciation. 



The photographs have been taken by the writer, using a folding 

 film camera, Ansco films, and tank development. 



Physiography and Origin 



The chief sand deposits of Illinois lie in the northern half of the 

 state, between latitude 40° and 42° 30'. In the southern half sand 

 occurs only in small local deposits or in bars near the larger rivers, 

 and is never of such extent that a peculiar vegetation is developed 

 upon it. Banks and bars of sand also border the streams of northern 

 Illinois, but their vegetation bears little relation to that of the larger 

 deposits here described. 



For convenience the sand areas have been given names taken from 



