—E— 
Fink: LICHENS OF NORTHWESTERN MINNESOTA. 675 
locality has only diminished the number of common species (C) 
by one. Like the very similar Cladonza-Peltigera formation 
recorded above, this one is especially developed under the 
pines. Indeed, it hardly seems necessary to separate them in 
the region now under consideration. 
The adaptations of the plants of the formation are similar to 
those fully discussed under the Cladonia-Peltigera formation. 
Briefly then, the Pe/tigeras, having only an upper cellular cor- 
tex, lie flat on the substratum, while the C/adonzas, protected 
on all sides by a pseudo-cortex, rise vertically and become 
luxuriant in the moist and shaded habitat. 
Next in order I shall consider a number of formations some- 
what studied in the Lake Superior region in 1897, but not yet 
recorded for the state, as it was then found impossible to take 
sufficient data in the rapid survey of a region fully one fourth 
of whose lichen flora the writer had previously known only 
through herbarium specimens or not at all. In the second sur- 
vey of a somewhat similar region, I was able to take sufficient 
field notes upon which to base an ecologic study of lichen for- 
mations peculiar to the region as well as those previously 
known. These formations, new to the state, will be recorded 
for more than one place as far as possible. 
First of all I shall record the formation of the pine trees, 
naming it for the Usnez group which give character to this 
plant community : 
USNEI LICHEN FORMATION OF THE PINES (RED LAKE). 
Cetraria ciliaris (Acu.) Tuck. (cones). 
Cetraria juniperina (L.) Acu. var. pinastri AcH. 
Evernia prunastri (L.) Acn. (cones). 
Usnea barbata (L.) Fr. var. florida Fr. 
Alectoria jubata (L.) Tuck. var. chalybeiformis Acu. 
Theloschistes chrysopthalmus (L.) Norm. 
Parmelia physodes (L.) Acu. 
Physcia tribacia (Acu.) Tuck. 
Physcia hispida (ScHREB., Fr.) Tuck. 
Lecanora varia (EuRuH.) Nyv. (cones). 
Lecanora subfusca (L.) Acu. var. argentata (Acu.) (cones). 
Buellia parasema (Acu.) TH. FR. (cones). 
Calicium lucidum (Tu. Fr.) Fink. 
On approaching a pine woods one is impressed with an ap- 
