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' Salix discolor). The roots of the poplar barely penetrate 

 the soil, which is water-saturated in spring and early summer, 

 and often they lie on the surface for a rod or more. The 

 aspens attain at times a height of 60 feet and a diameter of 

 28 inches, but more commonly they are dense growths, 30 to 

 40 feet tall, and 4 to 6 inches in diameter. The ultimate fate 

 of these latter trees is the grove of scattered adults, all that 

 remains of the former hosts in the struggle for existence. 



In these aspen associations there is practically nothing her- 

 baceous that is characteristic, except that it is here that the rare 

 orchid Habenaria bractcata is most surely to be found. In the 

 small prairies that have been referred to as certain to be found 

 with every such association, and doubtless of Indian fire origin 

 (see later) a few species are ever present. Baptisia leucantha, 

 Polygala viridescens carpeting large areas, Koellia virginiana, 

 Gerardia tenuifolia, the rare G. auriculata, and a few plants 

 of Rumex Britannica, make up the list. As hinted, these 

 aspen flats were prairies of considerable extent in the days of 

 Indian control, and were continued as such by the habit of 

 firing the grass in spring that new and fresh growth might be 

 aflForded to the game of the region. When the first white men 

 came to the country about 1800, a horseman could ride through 

 the open woodland or through the openings in every direction. 

 With the coming of the whites there was a cessation of the fires, 

 and the lodgment and growth of the wind-snow aspen seed 

 on the moist open lands caused their gradual reduction to the 

 small open spots which are now so characteristic. 



Most of the soils on which these aspens grow are what locally 

 are termed '"hard pan," having a dense impervious clay subsoil 

 that renders the areas very marshy in spring. Usually in clear- 

 ing the woodland these places are the first to be grubbed out, 

 on account of the ease with which the laborer can remove the 

 tree, root and trunk. The surface roots aid greatly in this un- 

 dertaking. Properly fertilized and particularly so if holes are 

 dug through the hard pan for drainage, the land produces good 

 crops. This hard pan explains the formation of the wallows 

 before mentioned, which were very common on all such flat 



