Kern : Rusts on Cyperus and Eleocharis 



135 



species. There have been available about 300 collections (211 on 

 Cyperus and 82 on Eleocharis) from the United States, Mexico, 

 Central America, and the West Indies. Advantage was taken of 

 an opportunity during the spring of 191 8, to work in the Arthur 

 Herbarium, Purdue University Agricultural Experiment Station, 

 and the facilities provided by Professor H. S. Jackson, the advice 

 of Dr. J. C. Arthur, and the aid rendered by several assistants, 

 particularly Misses Evelyn Allison and Grace Wineland, and Mr. 

 H. R. Rosen, have been in a large measure responsible for the 

 results attained. Especial thanks are due Mr. Rosen for pains- 

 taking microscopic studies which were of the greatest value in 

 defining the limits of the species. Type specimens of the new 

 species are in the Arthur Herbarium. 



About a dozen species of rust have been described on Cyperus. 

 Five species are recognized in this paper. Four of the several 

 possible names are applicable and one new name is proposed. 

 Some of the established names are included in the synonomy and 

 four are excluded. They either represent species not in our range 

 or sufficient information is lacking to permit a proper disposition. 

 An annotated list of these is included. No i -celled teliosporic 

 form has been described on Cyperus. Fewer species of rust have 

 been described on Eleocharis. In North America we have known 

 two, as many more are described here. Much culture work needs 

 to be done. Only two of the nine species have their aecial stages 

 known and two are known in the uredinial stage only. 



Key 



Hosts belonging to genus Cyperus (or Kyllinga). 

 Urediniospore-pores 2, equatorial. 



Urediniospore-wall 1-2 ix thick, uniform. 



1. Piiccinia canaliculafa. 

 Urediniospore-wall 1.5-2.5 fi thick, frequently thicker above. 



2. Puccinia Cyperi-tagetiformis. 

 Urediniospore-pores usually 3 (in occasional spores 4 or 2), equatorial. 



Urediniospore-wall 1.5 fi, or less, thick. 



Urediniospore-wall nearly colorless, teliospore-wall 1.5-3 ix above. 



3. Puccinia antioquiensis. 

 Urediniospore-wall cinnamon-brown, teliospore-wall 3-5 /x above. 



4. Puccinia abrepta. 

 Urediniospore-wall 1.5-2^6 thick, teliospore-wall 7-12 fi above. 



5. Puccinia Cyperi. 



