5 . 
In Wood's Class Book of Botany a number of species are credited 
to Illinois. 
But in addition to all these sources of information, I have had 
an opportunity to examine the extensive collections of plants made 
by Mr. Robert Kennicott, Mr. Emile Claussen, and others, and y' 
exhibited at the state fair held at Chicago, in 1855. This collection 
besides adding quite a number to the species before known as 
belonging to the state, was of material aid in showing their 
listribution. 
It will be readily understood, therefore, that the following is a 
pretty full list of the plants growing naturally within the state of 
Illinois. Further researches will undoubtedly reveal some new 
treasures; but compared with the whole, their number will be small. 
A glance at the geographical position of Illinois, with a knowledge 
of her principal topographical features, will prepare us to look for 
a rich flora. Bordering on the great lakes; bounded on her whole 
western side by the great Mississippi river; with the valley of the 
V.'abash on the east, and of the Ohio on the south, she is almost 
entirely surrounded by water. The southern extreme of the state lies 
in latitude 3? deg., or nearly as far south as the lower part of 
Kentucky and Virginia, and has an elevation of only two hundred and 
seventy five feet at low water, at Cairo, ab ve the ocean level. Here 
are found quite a number of plants that do not extend into the 
central and northern portions of the state. These are distinguished 
in the following catalogue by the letter S. The north line of the 
state is in latitude 43 deg. 30 min., and partakes in a considerable 
degree of the character of the south part of the adjoining state of 
Wisconsin. The plants in the following list found here, and which 
do not -extend into the central and southern parts of the state, are 
distinguished by the letter N. 
The central portions of the state lie on a nearly uniform plain, 
whose average c levation is consideraoly belcw the level of Lake 
