Arthur and Holway : VIOLET RUSTS OF NORTH AMERICA. 641 



have been. As the hosts of these four species of violet rusts 

 are found in this country, the rusts may not unreasonably be 

 expected also. 



EXPLANATION OF PLATE XLVII. 



All figures photographed and engraved to the same scale, x 250 

 diameter. Each millimeter on the plate equals 4/z of original dimen- 

 sions. 



Figures i, 2 and 3. Puccinia Viola showing three sizes of teleuto- 

 spores : i, on V. elatior from Germany, Sydow's Uredineen, No. 33 ; 

 2, on V. adunca from Gunnison, Colo. ; 3, Viola sp. from Mexico, 

 Holway No. 3573. 



Figures 4, 5 and 6. Puccinia Violce showing especially large teleu- 

 tospores : 4, on V. blanda from Lansing, Mich. ; 5 and 6, both on V. 

 cognata from Sisson, Calif., taken from different sori. 



Figures 7 and Puccinia Violce showing especially thick-walled 

 uredospores : 7? on ^ glabetta from Bingen, Wash. ; 8, on V. primu- 

 Icefolia from Isle au Haut, Me. 



Figures 9 and 10. Puccinia effusa showing regular and irregular 

 spores ; 9, on V. Ntdtattii from Falcon Valley, Wash. ; 10, on V. 

 lobata from Dunsmuir, Calif. 



