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Amphispores of the Grass and Sedge Rusts. 



J. O. Arthur. 



( Abstract. ) 



The paper described and illustrated the uredospores and amphispores 

 of five species of Puvcmia from central United States, and one species 

 of Uromyces from Northern India, all occurring upon various kinds of 

 grasses; they were P. rexans Farl., P. Tripsaci D. & H., P. St i pee Arth., 

 P. tosta Arth.. P. Cruptandri E. & B., and V. RotthocUkc Arth. It also 

 described and illustrated the amphisiiores, the uredospores not being 

 known, of three species of Piiccinia from the United States occurring upon 

 different species of Carex; they were P. Curicis-strictxe Diet., P. atrofiisca 

 (D. & T.) Holw., and P. Garrettii Arth. These are all the species of rusts 

 so far known to possess amphispores. This kind of spore is the resting 

 or winter form of the uredospore. They are not uredospores. however, 

 acciu'ately speaking, because they show distinct structural differences, 

 often very great, and are correspondingly modified physiologically. 



