211 



mixed in with southern ones near their northern limits is signifi- 

 cant as it demonstrates that vegetation representing different 

 provinces can exist under the same environmental factors. 

 University of Michigan 



TWO SUBMERGED SPECIES OF UROMYCES 



By Frank D. Kern 



About twenty-five years ago Professor F. L. Scribner, of the 

 U. S. Department of Agriculture, sent samples of several grasses 

 infested with forms of Ustilaginales and Uredinales to Messrs. 

 Ellis and Everhart for study. Among these was a rust on the 

 leaves of Aristida from New Mexico which they were unable to 

 refer to any published species and which they therefore de- 

 scribed as a new species, Uromyces Aristidae Ellis & Ev.* There 

 is throughout the United States east of the Rocky mountains a 

 rather well-known Uromyces on species of Aristida which has, 

 since the publication of the name by Ellis and Everhart, naturally 

 passed as U. Aristidae. 



Recently the writer had opportunity to examine the type 

 specimen of Uromyces Aristidae Ellis & Ev. which is in the Ellis 

 collection at the New York Botanical Garden and was much 

 surprised to find that it is not at all like the ordinary form which 

 has received that name in most mycological collections. Only 

 uredinia can be found on the type specimen but they are so essen- 

 tially different from the uredinia of the common Uromyces, 

 especially in the presence of paraphyses and in the surface mark- 

 ings of the urediniospores, that there can be no possibility of 

 their belonging to the same species. Since there are no telia 

 on the type specimen it is not even certain that it is a Uromyces; 

 it might as well be a Puccinia so far as any character present 

 would indicate. Ellis and Everhart doubtless mistook the ure- 

 diniospores for the teliospores of a Uromyces, an error not in- 

 frequently made by the earlier mycologists. 



Strangely enough among all the specimens of rust on Aristida 

 not a one, belonging either to Uromyces or Puccinia, has been 



* Jour. Myc. 3: 56. 1887. 



