704 



MINNESOTA BOTANICAL STUDIES. 



the former place, which does not occur at the latter, and the 

 fact that the paleozoic limestones outcrop at the surface much 

 more frequently at the latter. The first difference is in favor of 

 the lichen-flora about Minneapolis, and the second favors that 

 about Fayette, as each of these substrata bears its character- 

 istic lichens. As will be especially noted toward the close of 

 these notes, these two differences about offset each other. The 

 tamarack swamps about Minneapolis have no parallel about 

 Fayette and furnish lichens not found, or rare, in other parts 

 of the region considered in this paper. Yet all of these lichens 

 occur about Fayette on one substratum or another, so that, in 

 the comparison, the former region will gain nothing. Minne- 

 apolis has the larger river and the lakes, but not a single lichen 

 has occurred near these bodies of water that is especially char- 

 acteristic of such localities. However, these bodies of water 

 give the region a peculiarity of lichen distribution which can 

 scarcely escape the notice of an experienced collector. It is 

 that the number, both of individuals and species, is noticeably 

 greater about the lakes and river than in places somewhat 

 remote from them. 



The following table, giving the genera and the number of 

 species in each for the Minneapolis and Fayette vicinities, will 

 be instructive and will form the basis for some further com- 

 parisons of the two regions. 



Genera. 



Aeolium 



Arthonia 



Al.ectoria 



Kiatora 



Buellia 



Cetraria 



Cladonia , 



< 'ollenia 



Conioeybe 



Endocarpoii 



Evernia , 



Gyalecta .. . 



*• rap hi* 



Heppia 



Ijecanora , 



I^ecitlea 



Iieptoginm.. 



No. of 

 species. 



Mpls. 

 ... 1 



No. of 



species, 



Fayette. 



1 



5- 1 

 1 

 13— 3 

 5— 1 

 1 



16 



7- 1 

 1 

 6 

 1 



0— 1 

 2- 1 

 1 



16— 2 

 2- 1 

 5 



1— 1 



Genera. 



Opegraplia 



Pamiaria 



Parmelia 



Peltigera 



Pertusaria , 



Physcia 



Placodium 



Pyreimla 



Pyxine 



Ramaliiia 



It i nod in a 



Staurotbele .... 

 Theloscbistes 

 Urceolaria 



I SIH'Jl 



Verrucarla 



No. of 

 species, 



Mpls. 

 ... 1 



Totals 113 



No. of 

 species, 

 Fayette. 



2- 2 



2- 1 



9— 1 



6 



4- 2 

 10- 1 

 10- 1 



7— 1 



1 



3 



4 



1 



5 



1— 1 



4 



4- 1 



157-23 



Omplialaria 1 



The collecting at Fayette extended over three years, and 

 that at Minneapolis only over two months. Yet the collecting 

 at the former place was my first extended work on lichens, and 

 the best part of the work was confined to a single summer. 



