ECOLOGY OF ISLE ROYALE. 217 



NOTES ON THE VEGETATION OP ISLE ROYALE, MICHIGAN. 



W. p. HOLT^ CENTRAL HIGH SCHOOL, TOLEDO;, OHIO. 



I. General Observations on the Plant Societies. 



Situated in the northern part of Lake Superior, in sight of the 

 •Canada shore, and bisected by the parallel of 43° N., Isle Boyale offers 

 a most attractive field for summer work. That its flora is strikingly 

 northern may be inferred from its proximity to the Canadian shore, as 

 ■well as by the many species of northern plants included in the anno- 

 tated list of plants. 



The island, 45 miles long and containing about 210 square miles, has 

 had almost no permanent population since the "copper days;" and only 

 a few localities along the water's edge are frequented by summer visitors, 

 thus leaving the island largely free fromi man's occupancy. With the 

 exception of the buildings and mining improvements of the Wendigo 

 Mining Company, at the head of Washington Harbor, little remains on 

 the island to mark the vanished population, except the burnings and 

 clearings, which are easily recognized by their characteristic floras. 



Large parts of the island, however, have remained quite free from 

 man's invasion. That the present natural conditions are not likely to 

 remain long undisturbed, and that the past summer's observations and 

 records were made none too soon, is shown by the fact that contemporane- 

 ous with the work of the Museum party there were at least three differ- 

 ent parties of timber estimators working over large parts of the island 

 looking toward the cutting off of the forests. 



TTie general plan of the summer's work on the biota of the island was 

 to select the most typical and representative parts as general stations, 

 working these through sub-stations as carefully as time would allow, 

 and comparing other similar localities with these. 



The principal plant societies of Isle Eoyale may be considered under 

 four heads, viz.: Bog societies, shore societies, forests, and burnings. 



I. Bog Societies. It is doubtful if there could be found anywhere 

 in an area of the same size a more interesting and more complete series 

 of bogs than occurs on Isle Royale. On the geological map of the 

 island, by Lane and Stockly, there are shown over 100 smaller bog 

 areas, exclusive of the extensive bog region in the southwest part of the 

 Island, to the west of Siskowit Bay. Add to this the various stages 

 of partly filled lakes, and there is shown almost every conceivable stage 

 in the life history of bogs, from the open tarns, or lakes, to the climatic 

 bog forest. 



It is unnecessary to call attention to the very interesting manner in 

 which the bog fioras respond to the various stages of physical changes ; 

 such responses of vegetation in any physiographic series are too well 

 known to need comment. For any student who desires to work out in 

 detail these stages of successions as carefully and minutely as Cowles 

 has done for the dunes of the Chicago region, Isle Royale ^presents all 

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