FLOWERING PLANTS AND FEBNS OF INDIANA. 563 



the swamps covering thousands of acres that hang heavily along the 

 banks of the Wabash in its lower stretches and isolated patches at 

 every pond and lakelet or wherever there exists a sluggish, low-banked 

 stream. The continuous areas are those in the Kankakee region in the 

 northwest, and the cypress swamps in the extreme southwestern coun- 

 ties. In these regions water-loving plants dominate vegetation and 

 give their peculiar cast to landscape features. 



The dry plant, or Xerophyte, regions are found chiefly in the north- 

 ern parts of the State. The only continuous area is a relatively narrow 

 fringe along the shores of Lake Michigan, where desert plants and 

 those showing alpine or arctic characters, struggle as best they may for 

 a precarious livelihood along the beaches, or gain a firmer footing upon 

 some captured dune somewhat further back from the shores. Isolated 

 areas are also found, chiefly in the northern portions of the State, 

 where bare sand ridges or "barrens," dating back to glacial times, fur- 

 nish somewhat similar conditions. In other parts of the State an occa- 

 sional ancient river beach or bar may give a sharply limited home for 

 plants of this type. 



The remainder of the State, constituting by far its larger part, fur- 

 nishes the intermediate plant or mesophytic area. Wherever these 

 regions meet there is an overlapping of forms. Intermediate plants 

 developing adaptations for increased moisture conditions invade the 

 territory of the water-loving plants, and the hydrophytes retaliate by 

 an invasion of the intermediate area. 



Where drainage upon a large scale has been introduced, sharp 

 changes in the water content of the soil and in the soil water level have 

 of course resulted. In such regions equally sharp changes must have 

 occurred in the flora. Existing forms have either taken on adapta- 

 tions for the new conditions or must have given way to other forms. 

 How great these changes are at times has been shown by W. W. Chip- 

 man 1 in his studies of the successive floras inhabiting a definite area. 

 In this case no less than three floras of distinct type followed each 

 other within a period of six or eight years. These changes of the soil 

 water level do not merely affect herbaceous forms of annual or bien- 

 nial habit. At times they affect forest trees, a fact shown by the 

 death of beech trees, which followed extensive drainage operations in 

 various counties of the State. The root habit of the beech furnishes 

 the reason for its more ready yielding to changed water conditions. 

 Considerable forest areas, however, of mixed forms have shown a de- 

 cided depreciation in value in regions where drainage operations have 

 been extensive. 



L Proc. Ind. Aoad. Sci., 1896, pp. 147-158. 



