STATE HORTICULTURAL SOCIETV. 37 



certain leaf functions, that are dependent for their proper discharge on 

 the atmosplieric conditions of cold, heat, moisture, dryness, winds, etc., 

 as adapted to the nature of that particular tree. The tree cannot survive 

 unless it can perform these vital functions with at least tolerable success 



It is conceivable, also, and may be assumed as a matter of fact, that, 

 the conditions of soil and climate being propitious for tree growth, the 

 seeds of trees may be wanting, and that for long periods, a region once 

 unfavorable to tree growth may, after it becomes fit for tree growth, be 

 destitute of trees, simply because the seeds of those trees have not been 

 transported thither. And finally, a soil and climate that may grow trees, 

 once planted and rooted, may be unfavorable to the germination of seeds, 

 except in rare seasons, and a few places ; so that even though trees have 

 not sprung up spontaneously, they may, with due care and attention, be 

 planted and established so as to live a reasonably long life. 



When we examine a region, then we will naturally inquire which of 

 these various conditions prevails, and may predicate success with greater 

 or less confidence, accordingly. Our Illinois region being just without, 

 and indeed almost surrounded by, a forest country, it may be safe to 

 assume that there is no inherent difficulty in the way of climate tliat does 

 not also exist in the adjacent wooded regions, to nearly the same extent. 

 But it is true that in the West, at least, we must expect a permanent dis- 

 ability in securing the perennial vigor and centennial life that is attained 

 in climates of fewer extremes. \Ve have, I believe, absolutely no old 

 orchards, as compared with western New York and New England ; and 

 compared with the long tenacity of life shown in the moist atmosphere of 

 England, our trees are apparently ephemeral. They grow large and 

 rapidly; they furnish valuable timber, but they do not endure, after 

 reaching maturity, like the European trees standing in a climate equable 

 in moisture and warmth. I believe this difference is least apparent on 

 our Atlantic seaboard, and increases westwardly, as we lose the influence 

 of the sea, and is intensified until it becomes quite unfavorable to tree 

 growth in the extreme droughts and the intense cold of our western 

 plains. This is the common evil of the Prairie region. 



But concerning Illinois : We find a minimum of woodland in Ford 

 county; and the adjoining counties of Livingston and Grundy come 

 next in the scale. This part of the State, you will notice, is the region 

 of the sources of a number of small rivers, flowing in all directions, 

 among which are the Vermillions, the Kankakee, Sangamon, Mackinaw, 

 and Okaw, implying that here a shallow lake has been drained off in 

 various directions. It is as complete an example as can be had, perhaps, 

 of Lesquereux's theory of the Formation of the Prairies, as given in tlie 

 first volume of our Geological Report. This theory, in the language of 

 its author, is, " That all the prairies of the Mississippi valley have been 

 formed by the slow recess of sheets of water of various extent, first trans- 

 formed into swamps, and by and by drained and dried." "It gives," 

 he says in another place, " the reason of the presence of the prairies from 

 the base of the Rocky mountains to the borders of the Mississippi river ; 



