The American Botanist 



VOL. XIX JOLIET, ILL., MAY, 1913 No. 2 



7j/ie goicten nurslings of the 9^ay 



Sn splendor strew the spangled green, 



^nd hues of tender beautg plag, 



Entangled where the willows lean. 



TT^arJc how the rippled currents flow; 



Tl^hat lustres on the meadows lie/ 

 J^nd hark/ the songsters come and go, 



J^nd trill between the earth and s/cg. 



— Stedman. 



THE ORIGIN OF THE PLUM ISLAND FLORA 



By Willard N. Clute. 



I ' HE Chicago Plain, which extends in a broad beU around 

 the southern end of Lake Michigan and on which the 

 city of Chicago is built, is essentially a prairie, though one 

 which differs in scA'cral respects from the ordinary type on 

 account of its origin and soil characteristics. Originally the 

 bottom of a shallow lake, and at present raised less than twenty 

 feet above the level of Lake Michigan, its nearly level surface 

 is covered with a flora in which prairie plants OA^erwhelmingly 

 predominate, though many of these belong to the "low prairie" 

 association and delight in moist and swampy spots. 



The moraine, which forms the western and southern 

 border of the plain and once held back the waters of glacial 

 ^Lake Chicago, is well forested, but there are practically no trees 

 or shrubs on the plain with the exception of an occasional 



