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., Alectoria jubata (L.) Tuck. 
and Cetrarza 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. /t:nodina sophodes (Ach.) Nyl. and Arthonia lectdeella 
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 111 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 
