PAPERS OX BIOLOGY AND AGRICULTURE 



157 



limited experience, by the frequent reports of plantings 

 occnrring in or near limestone quarries. As time has 

 progressed, reports of barberries comfortably natural- 

 ized in many other situations, such as, for example, 

 among the dunes of Michigan and the shales in Illinois, 

 have indicated that some other explanation for habitat 

 must be sought. The wide range of habitat is indicated 

 by Kern (8) for Pennsylvania, as in ''residual soils, 

 whether formed from sandstone or shale, limestone, 

 igneous and metamorphic rocks. Glacial soil seems to be 

 equally favorable. * * * In thickets, along streams, along 



Map 7. DuPage County. Scale i4" = l mile. Markings same as Map 



