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THE CLIFF FLORA OF JO DAVIESS COUNTY. 



H. S. Pepoon. 



Nearly all the numerous streams that drain Jo Daviess county 

 and, after a longer or shorter southwest course, discharge their 

 waters into the Mississippi River, have their narrow, alluvial "bot- 

 toms" bordered by limfestone cliffs of varying height and ex- 

 tent. These cliffs are a marked feature of the landscape, and 

 by reason of their precipitous nature make roads having an 

 east and west direction a very difificult proposition, and ordi- 

 nary tramping across the country very difficult, and in many 

 places absolutely impossible. In height there are all variations, 

 from a low wall of rock, easily overlooked and overtopped by 

 a man of average stature, to towering and vertical precipices. 



Regarding the physical condition of the cliffs, there is to 

 be found a great degree of diversity, according to the direc- 

 tion and amount of exposure, the amount of sunlight received, 

 the water content of the rocks, and, to a limited extent, the 

 diverse physical constitution of the rock itself. Some cliffs are 

 dry as dust, others are constantly dripping cold clear lime- 

 water ; some never see the sun's rays, and others receive the full 

 effect of the midday sun; while in exposure all gradations are 

 found, from the sheltered nook, where a cold blast never pene- 

 trates, to a bald cliff exposed to the full fury of the north wind. 

 All the rock is limestone and of the Galena and Niagara for- 

 mations, but some variation is to be noted in the amount of 

 sandy admixture, or in the narrow zones of chert at varying 

 levels. 



Practically all the plants found on these circumscribed and 

 seemingly inhospitable rocks may be grouped with those of 

 xcrophytic or hydrophytic tendencies, but it is to be predicated 

 that many of the latter arc really watcr-xerophytes, if such a 

 term may be used for plants that, by all sorts of protective 



