Flora of Peoria. 38 
and this area is plowed and cultivated, or where the land has been closely pas- 
tured, it is plain. But where a species is adapted to a large section or coun- 
try and none of these conditions exist, why it should fail to grow, or if it has 
grown there and run out, I cannot explain. 
There is no locality in which everything grows which is capable of growing 
for the reason that everything has not been introduced. This is especially 
true of islands in the midst of the ocean. Islands far from the main land, 
while they may be rank with vegetation, are usually barren of species. The 
same is true of the Fauna of these islands for the same reason— they have not 
been introduced. Along Kickapoo Creek a few miles below the city there is 
much ground adapted to the hardy species of Ericacez, yet there are but two 
species found there and they are limited to two little spots which both together 
do not exceed one acre. Probably these have been there but a short time and 
no others have been introduced at all. 
The figures given above of the number of species must be taken as proxi- 
mate not absolute. The exact number of species in any locality can never be 
given, for the reason that classification is more or less arbitrary and no two 
botanists will ever agree exactly. 
The distinction between genera are not always clearly marked, and between 
species are less so, and between species and varieties the line of demarcation is 
often very indistinct. Take for example our asters; there are at least half a 
dozen of species according to otir present classification, of which characteristic 
specimens of each may be obtained, yet they run into each other interminably, 
so much so that more specimens are found which cannot be placed in any one 
of them tuan there are which can be. The fact is they are probably all one 
polymorphus species. This can only be determined by planting them all on 
the same ground and watching their development. 
Twenty years ago Prof. Gray told me, if he could get the time and muster 
the courage he would revise the asters. He has not done it, and no man can 
do it successfully until what I have indicated has been done. And what I say 
of the asters is equally true of many other genera. 
The only way to get an accurate knowledge of the flora of the world is for 
local botanists to work up the flora of every section of it. This of course can- 
not be done for many centuries, but by systematic effort the flora of the United 
States may be placed in an advanced stage in the course of fifty or an hundred 
ears. 
z Dr. Brendel and myself have been working this field the last thirty years, 
and latterly Miss Heading has worked a part of it. We do not claim to have 
done very much, but we have in our way, contributed our mite to the ad- 
vancement of the science of botany. 
