﻿SOME TALUS CLADONIA FORMATIONS. 



Bruce Fink. 



(with five illustrations) 



During the summer of 1897, while studying the lichen flora 

 of the north shore of Lake Superior, the luxuriance of certain 

 lichens growing on talus attracted attention. The field work was 

 being done for the Minnesota Botanical Survey, and an illustra- 

 tion of one of these unusually large lichens, a cluster of Cladonia 

 rangiferina two and one-half feet in diameter and standing fully 

 ten inches high, has already appeared in Minnesota Plant Life. 

 During the summer several talus lichen societies were hastily 

 examined, and it soon became apparent that luxuriant growth is 

 by no means the only interesting feature of such plant societies. 

 The object of the survey was taxonomic rather than ecologic, 

 and in a field where many of the lichens were new to the writer, 

 it was found to be practically impossible to secure the data neces- 

 sary for a study of ecologic problems without seriously interfer- 

 ing with the main object of the expedition. Not until the 

 summer of 1902 was it again found possible to visit the region 

 and secure the desired data. Of course the tali studied in both 

 years all lie within the state of Minnesota. During the season of 

 1897 tali were observed and somewhat studied along the inter- 

 national boundary between Grand Portage and Gunflint, and 

 farther south at some distance inland in the Misquah Hills, as 

 well as in the Sawteeth Mountains along the shore of Lake 

 Superior. In 1902 efforts were confined to the region along the 

 lake shore, an area not easily equaled in interest as to lichen 

 flora. 



On the whole it may be said that such talus lichen societies 

 as will be considered in this paper are among the most interest- 

 ing of lichen communities. Yet it must be added that they are 

 quite as rare as interesting, or that, growing where they are very 

 difficult of access, they are rarely seen. The composition of such 



1903] 



I9S 



