XIX. CONTRIBUTIONS TO A KNOWLEDGE OF 



THE LICHENS OF MINNESOTA. V. LICHENS 



OF THE MINNESOTA VALLEY AND 



SOUTHWESTERN MINNESOTA. 



BRUCE FINK. 



CONSIDERATIONS OF DISTRIBUTION AND HABITAT. 



The area considered in this paper was selected with a view 

 to obtaining as complete a knowledge as possible of the lichen 

 flora of the Minnesota river valley and of that of southwestern 

 Minnesota in general. 



The upper portion of the valley near Minneapolis would, of 

 course, give a flora essentially like that of Minneapolis and vi- 

 cinity already studied. Hence, for the month's field work, it 

 was thought best to begin operations at a locality a considerable 

 distance from Minneapolis. As an initial place, Mankato, about 

 60 miles from Minneapolis, was selected. The location of this 

 city is also advantageous in that it lies nearly midway between 

 the Minneapolis and the northeastern Iowa areas compared 

 carefully in the second paper of this series, thus forming a con- 

 necting link between the two areas previously studied. After 

 a careful study of the lichens of the Mankato area both to gain 

 a knowledge of the lichen flora of the region and for the sake 

 of relationships with the areas indicated above, New Ulm was 

 next selected as an area of special interest because of the expo- 

 sures of Cretaceous sandstone and the most southeastward ex- 

 posures of quartzite rocks in the valley. At New Ulm only 

 these two rock formations were studied, as time spent on other 

 substrata present would only be repaid for most part by a repe- 

 tition of the species found upon the same substrata at Mankato, 

 only 30 miles distant. Three days were next spent at Red- 

 wood Falls, Morton and North Redwood with a view to secur- 

 ing rare species and noting the southeastern extension of certain 

 species in the valley. From here I proceeded to Granite Falls. 



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