ECOLOGICAL RELATIONS OF THE FLORA. 61 



The fungi lists are given to show that this layer responds to the en- 

 \nronmental factors even as the higher plants do. Allowing for 

 differences in life relations, fungi also come under the laws of 

 ecological succession. 



The phytogeographic relations of this area show that it is now in a 

 transition zone where pronounced northern and southern species are 

 found. The genetics and climax group in this location as compared 

 with other points on the Great Lakes show that the whole region is 

 becoming a phytogeographic unit, and, while the division into northern 

 and southern forms, and Engler's separation of the White Pine area 

 into Eastern and Western regions, are now justifiable, the Great Lakes 

 drainage sj'stem is becoming a stable province, with northern and 

 southern species growing in the same localities, but sorted out into 

 associations by edaphic conditions. 



LITERATURE CITED. 



Adams, C. C. 



1902. Southeastern United States as a Center of Geographical Dis- 

 tribution of Flora and Fauna. Biol. Bui.. 3: llo-L31. 

 1902. Post Glacial Origin, and Migration of Life in Northeastern 



Tnited States. Journ. Geog.. 1:303-310: 352-357. 

 1905. Post Glacial Dispersal of North American Biota. Biol. Bui., 

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 Bailey, L. H. 



1880. Michigan Lake Shore Plants at South Haven. Bot. Gaz., 

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 Beal, W. J. 



1888. Observations on the Successions of Forests in Northern Mich- 

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 1904. Michigan Flora. Rept. Mich. Acad. Sci., 5. Reprinted by 

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 Buller, A. H. R. 



1909. Researches on Fungi. London. 

 Bureau of Soils. 



1901. Soil Survey of Allegan County, Michigan. 

 Chamberlain. T. C. 



1877. Native Vegetation of Wisconsin. Geol. of E. Wis.. 2: 176-188. 

 Coulter, S. M. 



1904. Ecological Comparison of Some Typical Swamp Areas. Rept. 

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 Cowles, H. C. 



1899. Ecological Relations of the Sand Dunes of Lake Michigan. 

 Bot. Gaz.. 27:95-117: 167-202: 281-308: 361-391; figs. 

 1-26. 



