112 MINNESOTA BOTANICAL STUDIES. 



to the east of which lie the great prairies with rainfall sufficient 

 to insure perennial fertility, while to the west there is what the 

 early explorers called the Great American Desert, stretching to 

 the base of the Rocky Mountains, suffering from a deficiency 

 of rainfall. 



This climatic condition, approaching semi-aridity, appears to 

 have come on gradually, if we may judge from the considerable 

 number of stunted, starved and sterile species that were col- 

 lected, several of which it has not been possible to determine 

 satisfactorily. Of the ninety-six species worked out forty -four 

 are new to the state, that is, have not been reported before. Of 

 these, six are new species. 



Finally, grateful acknowledgment is due to the following 

 persons : to Dr. A. J. Grout for naming the species of Brachy- 

 thecium and Eurhynchium ; to Dr. G. N. Best for naming the spe- 

 cies of Anomodon^ Leskea and Thuidium; to Mrs. E. G. Britton 

 for naming species of Orthotrichum; to Prof. L. S. Cheney 

 for naming a number of species, principally Amblystegium ; to 

 Messieurs Cardot and Theriot for naming the species of Bryum 

 and of several other genera ; to M. F. Renauld for naming 

 species of Hypnum, principally of the section Harpidium, and 

 to Dr. N. Bryhn for naming the species of Philonotis. 



Following is the list of additions to the moss flora of Minne- 

 sota : 



Amblystegium brachyphyllum CARD. ET THER., n. sp. 



Amblystegium brevipes CARD. ET THER., n. sp. 



Amblystegium compactum (C. M.) AUST. 



Amblystegium trriguum (WiLS.) B. S. 



Amblystegiilm riparium trichopodium BRID. 



Archidium ohioense SCH. 



Astomum crispum HPE. 



Brachythecium cyrtophyllum KINDB. 



Brachythecium rivulare B. S. 



Bryum cap? liar e flaccidum BR. EUR. 



Bryum holzingeri CARD. ET THER., n. sp. 



Bryum meesioides KINDB. 



Bryum minnesotense CARD. ET THER., n. sp. 



Bryum obconicum HSCH. 



Bryum pseudotriquetrum SCHW. 



Catharincea macmillani HOLZ. 



Ceratodon conicus HPE. 



