STUDIES IN PLANT DISTRIBUTION. 

 By Ernest Brunckjsn. 

 9. The Shore of Lake Michigan. 

 (For pre: ions articles in this scries, sec Proceedings, JQ02.) 



The immediate neighborhood of Lake Michigan has a floristic 



and ecological character so distinct from the rest of the Milwaukee 

 region, that it deserves separate consideration in any study of the 

 plant distribution in the vicinity of Milwaukee. In the following 

 pages it is not attempted to furnish an exhaustive list of the species 

 occurring in this area. Such a list ought to be made and will un- 

 doubtedly throw further light on the matters here discussed. Bat 

 the present aim is simply to give a description of the general fea- 

 tures of the area and offer some suggestions regarding their ex- 

 planation. 1 



The character of a given area is determined by two sets of 

 factors, one physical, the other historical. The physical factors are 

 the sum of the edaphic and climatic influences active at any given 

 moment ; the historical factors include all changes that have ever 

 taken place in these physical conditions as well as in the organic 

 life of the area. Both sets of factors are interdependent and can- 

 not really be separated from each other. 



It is the aim of this discussion first to describe the present con- 

 dition of Lake Shore vegetation, and secondly to inquire into the 

 manner in which this condition has been brought about by the two 

 sets of factors mentioned. 



A. Physio graphical Character. 



The area discussed extends from a little south of the north line 

 of Racine County to the south line of Ozaukee County, an extent, 

 following the sinuosities of the shore, of about 25 miles. The whole 



"T> It may be said that the publication of an account admittedly so 

 fragmentary is premature. The author's excuse is that probably he will 111 

 the future have very limited opportunity lo continue lis studies m this partic- 

 ular region. 



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