290 MINNESOTA BOTANICAL STUDIES. 



We may now turn to the lichen formation of shaded or damp 

 rocks at Granite Falls. This includes some flat rock surfaces 

 somewhat shaded or simply wet part of the time, as well as the 

 perpendicular shaded surfaces. I shall divide the formation 

 into three parts species naturally belonging to the rocks, those 

 which have probably migrated from the trees near at hand and 

 those which have probably migrated from the earth. Here and 

 in another formation we have a mixture of elements, hence the 

 following name is proposed : 



Mixed formation of shaded (or damp] granite (Granite Falls). 



A. PROBABLY NATURALLY BELONGING TO THE ROCKS. 

 Ramalina polymorpha (Acn.) TUCK. 



Ramalina calicaris (L.) FR. var. farinacea SCIIAER. 



Pannaria microphylla (Sw.) DELIS. 



Pannaria languinosa (AcH.) KOERB. 



Omphalaria phyllisca (WAHL.) TUCK. 



Collema furvum (Acn.) NYL. 



Leptogium lacerum (Sw.) FR. 



Endocarpon muriatum (L.) SCHAER. 



Staurothele umbrina (WAHL.) TUCK. 



Staurothele diffractella (NYL.) TUCK. 



Staurothele drummondii TUCK. 



B. NEAR TREES AND PROBABLY MIGRATED FROM THEM. 

 Parmelia cetrata ACH. 



Parmelia crinita ACH. 



Parmelia borreri TURN. 



Parmelia borreri TURN. var. hypomela TUCK. 



Parmelia saxatilis (L.) FR. 



Parmelia saxatilis (L.) FR. var. sulcata NYL. 



Parmelia saxatilis (L.) FR. var. panniformis (Acn.) SCHAEK. 



Parmelia caperata (L.) ACH. 



Physcia speciosa (WULF., ACH.) NYL. 



Physcia pulverulenta (SCHREB.) NYL. 



Physcia obscura (EHRH.) NYL. 



Pyxine sorediata FR. 



Leptogium myochroum (EHRH., SCIIAER.) TUCK. 



