184 IOWA ACADEMY OF SCIENCES. 



After giving this brief summary it may be stated that the 

 decrease in richness of lichen-tiora changes to an increase 

 somewhere between Minneapolis and Duluth, as will be brought 

 out in a future paper on the lichens of Minnesota. 



As regards other Iowa problems, the most interesting region 

 in connection with the study here presented is that extending 

 along the Mississii3pi river from the northeastern region 

 already studied to the southern extremity of the state. The 

 study of this area, besides the information it would furnish 

 concerning the lichen-flora of our own state, is especially nec- 

 essary to an understanding of lichen-distribution along the 

 upper Mississippi river. The study of more western portions 

 of Iowa will bring new problems and also throw some light on 

 those here considered. 



Below is added the lists of new and rare Iowa lichens men- 

 tioned in the first part of this paper. These with two given 

 for locality bring the total number of species and varieties 

 which I have collected and determined at Fayette up to 208. 

 These additions make a total of 226 species for the state, and 

 this number could be increased largely by thorough work in 

 several widely separated regions within Iowa. 



LIST OF SPECIES NEW TO IOWA. 



Usnea barbata L. Fr., var. ceratina Schser. On trees, rare. 

 Fayette. 



Alectoria jubata L., var. chalybeiformis Ach. On an old board 

 fence, rare. FayetLe. Also on Saint Peter sandstone in Clay 

 ton county. 



Theloschisfes concolor Dicks, var. effusa Tuck. On trees, rare. 

 Fayette. Since publishing the first paper on Iowa lichens I 

 have also found at Fayette a form of the species with fibrils 

 unusually developed about the apothecia. They are frequently 

 as long as the diameter of the apothecia! 



Pormelia saxatalis L. Fr., var. sulcata Nyl. On trees, rare. 

 Fayette. 



Parmelia oUvacea L. Ach., var. a.spidota Ach. On trees, infre- 

 quent. Fayette. 



Pannaria nigra 'Nyl., var. ccesia Nyl. On calcareous rocks, 

 rare. Fayette. 



Collema nigrescens Huds., Ach. On old logs, rare. Fayette. 

 Frequently with pruinose apothecia. 



