﻿1 9 03 J CLADONIA FORMATIONS • 199 



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youngest of the lichen-bearing tali studied. Of course fires 

 have run over certain tali and destroyed the plant life. In such 

 instances the age may, for our purpose, be estimated from the 

 time when the fire destroyed the lichens and other plants; for 

 we are really interested in the age of plant societies. 



On the old talus at Hat Point the lichen clusters, in the 

 more shaded spots, are being driven out by the mosses, and the 

 lichen-formation may be said to be scattered.' Yet the Clado- 

 nias of such societies are the most luxuriant known to the writer. 

 On the tali which seem younger, or which do not present quite 

 so purely ombrophytic conditions, the lichens occupy nearly the 

 whole of the surface. The last formation to be considered 

 below is such a one. Before passing to consider the individual 

 formations it may be well to state that the Cladonias are found 

 so densely congregated upon certain tali because better adapted 

 to the environment than other plants, with which they cannot 

 cope so successfully in the surrounding woods, though the 

 lichens of the tali occur more or less commonly in the woods 

 also. Further it may be said that these Cladonia societies of the 

 tali always attract notice and special interest. 



Passing to the consideration of the formations, the one that 

 has been designated the Clado7iia gracilis formatio?i of shaded 

 talus may be taken up first. The lichen society of this type to 

 be considered especially occurs upon the talus on the north side 

 of Howenstine Bluff, about a mile west of Grand Marais Bay, at 

 Grand Marais, and is the best example of such lichen society 

 known to the writer. The bluff faces to the north and rises 

 forty-five feet above the level ground at the base to the north- 

 ward. The lower two-thirds of the face of the bluff is covered 

 with talus blocks of various sizes, and the face of the talus rises 

 at an an^le of about 35°. The base of the talus lies about forty 

 feet away from the base of the bluff face, and fully one-third 

 and in some places half way up from the base the talus is 

 covered with a more or less dense growth of trees of moderate 

 size, whose branches overhang the talus rather more than half 

 way up to the bluff face. Thus taking into account both the 



'Fink, B., Minnesota Botanical Studies 2:300. 1899. 



