THE ECOLOGICAL SUCCESSION OF MOSSES, AS ILLUS- 

 TRATED UPON ISLE ROYALE, LAKE SUPERIOR 



WILLIAM S. COOPER 



Carmel, California 



During the course of ecological study upon Isle Royale, Lake 

 Superior, the importance of the mosses in the various succes- 

 sions leading up to the establishment of the final forest vegeta- 

 tion was strongly impressed upon me. The general results of 

 the work are soon to be published elsewhere, but it may serve a 

 useful purpose to summarize in a separate paper the observations 

 relating particularly to the mosses. At the commencement of 

 the investigation I was making my first acquaintance with most 

 of the species, and the results are therefore not as complete as 

 they would have been had the work been done by an expert in 

 the group. The purpose of this paper is simply to point out the 

 important part which the mosses play in certain plant succes- 

 sions, and to suggest some of the possibilities of an undeveloped 

 field of study. A list of the species collected upon the island, 

 about ninety in number, is soon to appear in the Bryologist. 



Isle Royale is situated in the northwestern part of Lake Supe- 

 rior, parallel to the Canadian shore and about 25 km. distant 

 from the nearest point of the mainland. It is a large island, 

 being 70 km. long and 13 km. wide at the widest part. The 

 topography is striking. A series of straight even-topped ridges 

 extends from end to end, steep-sided on the northwest, sloping 

 gently southeastward. Between these are long narrow parallel 

 valleys, continued at the ends of the island as fiord-like bays 

 bounded by rocky points, which are the extremities of the ridges. 



Yegetationally the island belongs within the Northeastern 

 Conifer Forest Region, although its proximity to the southern 

 limit of this territory is suggested by a small area of sugar maples 



197 



THE PLANT WORLD, VOL. 15, NO. 9, SEPTEMBER, 1912 



