Fink: LICHENS OF THE MINNESOTA VALLEY. 290 



Omphalaria sp. 



Leptogium lacerum (S\v.) FR., C. 

 Endocarpon miniatum (L.) SCHAER., C. 

 Placodium citrinum (HOFFM.) LEIGHT., C. 



The plants of the Minneapolis list are all but one common (C) 

 to both formations and may be regarded as characteristic of 

 such formations. Since the last formation is poorly developed, 

 I may add the similar one for Fayette, Iowa, which is better 

 developed than either of the above. 



Gelatinous lichen formation of shaded (or damp] calcareous 



rocks (Fayette, Iowa). 

 Pannaria nigra (Huos.) NYL. 

 Pannaria languinosa (Acn.) KOERB. 

 Omphalaria pulvinata NYL. ? 

 Omphalaria umbella TUCK. ? 

 Omphalaria sp. 

 Collema plicatile SCHAER. ? 

 Collema furvum (Acn.) NYL. ? 

 Collema pustulatum ACH.? 

 Leptogium lacerum (Sw.) FR. 

 Leptogium chlorometum (S\v.) NYL. 

 Placodium citrinum (HOFFM.) LEIGHT. 

 Biatora trachona FLOT. 



Buellia alboatra (HOFFM.) TH. FR. var. saxtcola FR. 

 Endocarpon miniatum (L.) SCHAER. ? 

 Staurothele umbrina (WAHL.) TUCK.? 



The introduction of the Fayette formation is of special interest 

 for the following reason. The first Minnesota formation is a 

 mile back from the Minnesota river on a bluff along which the 

 river once flowed, but which now is left dry except for the trees 

 which overhang it and shade the lichens of the formation. 

 The Fayette formation is on a bluff at the water's edge, and the 

 plants are growing within one to ten feet of the water. Doubt- 

 less this in part causes the greater richness. The Mankato for- 

 mation is an interrupted one, none of the plants persisting in 

 wholly unshaded spots. The .Fayette formation on the other 

 hand, extends for miles, without complete interruption, wher- 



