A LIST OF MOSSES COLLECTED UPON ISLE ROYALE, LAKE 



SUPERIOR 



William S. Cooper 



The following list is mainly the result of one season's collecting by a beginner 

 in the study of the mosses. To make the catalogue as complete as possible, 

 sixteen species, not seen by the writer, have been added from the report of Mr. 

 W. P. Holt, who collected upon the island during the summer of 1905,* and 

 whose list of mosses includes a total of thirty-eight. 



Isle Royale is a large island in the northwestern part of Lake Superior, dis- 

 tant 23 km. from the nearest point of the Canadian mainland. Vegetationally, 

 it is included in the region dominated by the great Northeastern Conifer Forest. 

 The Climax Forest of the island is composed mainly of Balsam Fir, Paper Birch, 

 and White Spruce, and is exceedingly mesophytic in character. The principal 

 lines of succession leading to its establishment are two. The Rock Shore Suc- 

 cession progresses through crustose, foliose and fruticose lichen, crevice, rock 

 pool, heath mat, and xerophytic forest stages to the climax state. The xero- 

 phytic forest, not always present, is composed of Jack Pine and Black Spruce. 

 The Bog Succession proceeds through aquatic, sedge, shrub-sphagnum, and bog 

 forest stages, the last being composed of Tamarack, with Black Spruce or Arbor 

 Vitae or both. Many of the mosses were found to have definite places and 

 roles in these successions, which I have described in a paper that is now in pro- 

 cess of publication in the "Plant World." 



For the identification of doubtful specimens and verification of my whole 

 collection, I am indebted to Miss Edith A. Warner, of Brooklyn, N. Y. 



Sphagnaceae 



1. Sphagnum actitifolium Ehrh. 



2. Sphagnum fuscum (Schimp.) Klinggr. 



3. Sphagnum Girgensohnii Russ. var. molle Grav., Holt. 



4. Sphagnum magellanicum Brid. 



5. Sphagnum papillosum Lindb. var. intermedium (Russ.) Warnst. 



6. Sphagnum platyphyllum Sull. var. suhsimplex (Ldbg.) Holt. 



7. Sphagnum recurvum Beauv. var. parvifolium Sendtn. 



8. Sphagnum rohustum (Russ.) Rl. var. gracile Rl., Holt. 



9. Sphagnum teres (Schimp.) ^nggtr. 



10. Sphagnum Warnstorfii Ru^s. 



The sphagna are as usual characteristic of the sphagnum-shrub zone of the 

 bogs, and persist frequently into the bog forest. 



*W. P. Holt. Notes on the Vegetation of Isle Royale, Michigan. In "An ecological 

 survey of Isle Royale, Lake Superior," prepared under the direction of Chas. C. Adams. 

 State printers, Lansing, Mich., 1909. 



