North American Species of Puccinia on Carex 207 



submitted to them. This work of host determination has been 

 tedious; the opening of the mycological packets and the fragmen- 

 tary condition of many of the specimens must frequently have 

 been irksone to phanerogamic botanists but these gentlemen have 

 most cheerfully responded to numerous requests for identifica- 

 tion. 3 



In making up the lists of hosts under the different species only 

 the names considered to be most acceptable are included, omitting 

 all which are regarded as synonyms. In order to make these 

 synonyms, some of which may be commonly known, also avail- 

 able they are included in the Index to Rusts Occurring on Vari- 

 ous Species of Carex at the end of this paper, with proper cross 

 references. 



The studies have been carried on over a considerable interval, 

 ten years or more, during which time the routine duties of teach- 

 ing and experiment station work have claimed the larger share of 

 effort, and yet there has been a continuous interest and numerous 

 periods of varied extent have been devoted wholly to this group. 

 The work which has been done directly with the idea of preparing 

 a monographic account has been made possible only by the initial 

 and continued support of Professor J. C. Arthur and his staff of 

 botanical assistants, among whom Miss Mary A. Fitch deserves 

 especial mention. The painstaking observations and careful rec- 

 ords made by Miss Fitch at a time when the whole matter was in 

 a very chaotic condition assisted very materially in establishing 

 a working basis. Five years ago a paper entitled A Revision of 

 the North American species of Puccinia on Carex was presented 

 in brief form by the writer before the Botanical Society of Amer- 

 ica. 4 Miss Fitch was included as a joint author but the paper 

 was published only in abstract form. 5 Since that presentation 

 the studies have been continued, but without the aid of Miss 

 Fitch, and the results of the more recent work are incorporated 

 in this paper. The value of the foundational work of Professor 

 Arthur and of his continued assistance cannot be overestimated. 



3 For notes concerning the activities of Dr. Holm see Torreya 13 : 72 

 (19 13) and Mycologia 5: 240-244 (19 13). 



4 Washington meeting, December 27, 191 1. 



5 Science, N. S. 35: 150. 1912. 



