Fink: LICHENS OF NORTHWESTERN MINNESOTA. 659 



hitherto recorded for various well-studied localities in the state 

 in this series of papers, we find the region slightly poorer in 

 lichens than any other region in Minnesota having as much va- 

 riety as to substrata. 



The next collecting station was at Henning, about 35 miles 

 to the northeast. This area was selected especially for the 

 study of the flora of the Leaf hills to the south of the town and 

 for that of the tamarack and spruce swamps, which were not 

 found farther southwest. Prominent among the floral elements 

 of the swamps are species of Usnea, Parmelia caperata (L.) 

 Ach., Parmelia saxatilis (L.) Fr., Alectortajubata(I^.)T\^.cVi. 

 and Cetraria ciliaris (Ach.) Tuck. Other species will be listed 

 toward the close of these considerations in the discussion of 

 formations. Passing from the swamps to the Leaf hills three 

 miles away, all of the above species become rare or entirely 

 wanting, though the two Parmelias are more frequent where 

 large trees extend, in a few places, to the tops of the morainic 

 hills. Rinodina sophodes (Ach.) Nyl. and Arthonia lecideella 

 Nyl., become abundant on the shrubs of oak, poplar and birch 

 in the hills. These hills probably reach an elevation of 1,800 

 feet south of Vining and form the hightest morainic area in the 

 state. The drift bowlders and pebbles of granite and limestone 

 extend to the very summits of the hills and furnish an excellent 

 field for the study of lichen formations, especially of granitic 

 bowlders. The calcareous matter of the drift has been ground 

 fine as powder or left as small pebbles. The soil contains 

 enough lime so that the lichen formation characteristic of cal- 

 careous earth is well developed, and the limy pebbles also 

 support a well developed calcareous rock-lichen formation. 

 Black peak about four miles south of Vining is an especially 

 good place for the study of the last two formations, which will 

 receive careful consideration later in this paper. It may be 

 noted in passing that the lichen flora of this second region is a 

 much richer one than that first studied near the border of the 

 wooded region, where the morainic hills are less developed, 

 where trees are less numerous and of fewer species and where 

 the tamarack swamps are wanting. In the region about Hen- 

 ning 140 species and varieties were collected in about the same 

 time as was required to find the in at Battle lake. 



Passing on to the next area studied at Bemidji 75 miles 

 north of Henning and well within the pineries where there is 



