ECOLOGICAL RELATIONS OF THE FLORA. 35 



ECOLOGICAL RELATIONS OF THE FLORA. 



BY G. H. COONS. 



In the summer of 1908, the writer was a member of the field party of 

 the Michigan Geological and Biological Survey which was at that time 

 conducting biological investigations in the sand region of Huron County. 

 As Mr. C. K. Dodge was engaged to make the exhaustive floral lists, 

 the writer restricted himself to the examination of the ecological re- 

 lations of the plants. The work was practically confined to Sand 

 Point, where the habitats were worked in as much detail as the time 

 (6 weeks in July and August) permitted. On account of the time hmi- 

 tations the work was necessarily very incomplete, but the wTiter submits 

 the following paper, trusting that the results are correct as far as they 

 go, and that the work will be a contribution to the subject. 



The results are presented according to the following outline: 



Physiographic Conditions. 

 Ecological Relations.* 

 Hydrophytes. 



Fresh Water Formations. 

 Chara As.sociation. 

 Xymphaea Association. 



Helophytes. 



1. Amphibious Formation. 



Scirpus Association. 

 Jmicus Association. 

 Carex A.ssociation. 



2. Reed Swamp Formation. 



Phragmites Association. 



3. Bush Swamp Formation. 



Alnus .\ssociation. 



4. Wooded Swamp Formation. 



Birch-Willow Association. 



Mesophytes. 



Forest Formation. 



Poplar-Birch-Maple Association. 



* The ecological nomenclature follows Warming's Oecologij of Planls . 



