294 MINNESOTA BOTANICAL STUDIES. 



Cladonia turgida (Ehrh.) Hoi fm. 



Biatora uliginosa (Schrad.) Fr. 



Endocarpon hepaticum Acii., CT. 



Endocarpon pusillum Hedw. var. garovaglii Kph,, C. 



Comparing these lists with the one given for the correspond- 

 ing formation at Pipestone, we find three common Hchens which 

 are marked (C) in the list above. Two of these marked (T) are 

 also found in the similar formation at Taylors Falls, and one 

 marked (S) is common in like formations in the lake Superior 

 region. This plant is the most constant element in the exposed 

 earth lichen formations of the State, and I should be disposed to 

 name these Cladonia -pyxidata lichen formations, were it not 

 that the plant, though commonly present in exposed stations, 

 thrives better in shaded ones. I must here emphasize that these, 

 as well as the calcareous-earth lichen formations, grow on earth 

 in rocky places where larger vegetation is scanty and scattered. 



Next in order come lichen formations of shaded earth, partly 

 composed of plants which grow also, though not so well, in un- 

 shaded places. From their dominant elements, these may be 

 designated as follows : 



Cladonia-Peltigera lichen formation of shaded earth 



(Mankato). 



Peltigera rufescens (Neck.) Hoffm. 



Peltigera canina (L.) Hoffm. 



Peltigera canina (L.) Hoffm. var. sorediata Schaer. 



Collema pulposum (Bernh.) Nyl. 



Collema tenax (Sw.) Ach. 



Cladonia pyxidata (L.) Fr. 



Cladonia fimbriata (L.) Fr. 



Cladonia gracilis (L.) Fr. 



Cladonia gracilis (L.) Fr. var. verticillata Fr. 



Cladonia-Peltigera lichen formation of shaded earth (Granite 



Falls). 



Peltigera rufescens (Neck.) Hoffm., CT. 



Peltigera canina (L.) Hoffm., CTS. 



Peltigera canina (L.) Hoffm. var. sorediata Schaer., CTS. 



Collema pulposum (Bkrnii.) Nyl., CT. 



