XVIII. CONTRIBUTIONS TO A KNOWLEDGE OF 



THE LICHENS OF MINNESOTA. — VII. 



LICHENS OF THE NORTHERN 



BOUNDARY. 



Bruce Fink. 



Considerations of Distribution and Habitat. 



During the summer of 1901, the writer spent eleven weeks 

 in field study of lichens for the Minnesota botanical survey, and 

 the following paper is the outcome of that work and subsequent 

 careful study of the material collected. In the study of the 

 Cladonias, Dr. E. Wainio has continued his valuable aid till 

 nearly 200 of the Minnesota collections within the genus have 

 passed through his hands, and the work of the whole genus 

 bears the impress of his remarkable knowledge of Cladonias. 

 Dr. A. Zahlbriickner has also examined more material since 

 the publication of the last number of this series, but little of his 

 work happens to contribute to the present paper. Moreover, 

 we have four^d in Dr. T. Hedlund, of Upsala, Sweden, a most 

 excellent helper in the genera JSiatora, Lecidea and Buellia, 

 and we are under lasting obligations to him as well as the two 

 men previously named for much aid in the work. 



The area considered in the present paper lies along the 

 northern boundary of the state from Warroad eastward by 

 south to Harding, thence southward to Tower. In order to 

 study the flora of a wooded region nearer the northern boundary 

 than Warroad, and at the same time well to the west, Oak 

 island, in Lake of the Woods, and some other islands near by, 

 were studied. The region covered by this paper was selected 

 with a view to obtaining as complete a knowledge as possible 

 of the lichen flora of the extreme northern portion of the state 

 and to supplement the knowledge recorded in the fourth and 

 sixth papers of this series. That the area was well selected for 

 the latter purpose will appear, and its richness is shown in that 

 the list of species and varieties has reached 312 as against 258 



167 



