640 MINNESOTA BOTANICAL STUDIES. 



The western coast of the United States in spring and early 

 summer. The following specimens have been examined, the 

 first being the type collection : 



On Viola lobata BENTH. 1894, Dunsmuir, Calif. I. iii (E. 

 W. D. Holway). 



On Viola Nuttallii PURSH. 1897, Falcon Valley, Wash. I. 

 iii ( W. N. Suksdorf}. 



The species is very characteristic. It probably possesses 

 sperrnogonia, but they have not yet been observed ; it is, how- 

 ever, without uredo, although erroneously included in the orig- 

 inal description of the species. Two specimens are cited 

 (Erythea 3 : 82) as type material, the first on Viola lobata, re- 

 ferred to above, and the second on Viola ocellata. The latter 

 specimen has been examined and proves to be Puccinia Violce, 

 and is cited above under that species. The original description 

 of the species is accordingly emended to omit the supposed 

 uredo. 



The difference in the shape of the spores, shown in the pho- 

 tographs of spores taken from the two hosts, is doubtless due 

 to some accident of growth, such as more or less compression 

 in the young sorus, and is without diagnostic value. It is of 

 the same nature as the difference shown in two mountings from 

 the same collection of P. Viola on V. cognata. The more 

 regular spores are to be accepted in each case as the normal 

 development under favorable conditions. 



Four additional species of violet rusts occur in Europe, and 

 it is possible that they may eventually be found in this country. 

 Uredo alpestris Schroet. inhabits Viola biflora L., and as this 

 host is a native of the Rocky Mountains, the rust may possibly 

 accompany it. Puccinia alpina Fckl. also occurs on V. bijlora 

 L., and P. Fergussoni'Qvfa. & Br. occurs on V. -palustris L., 

 and V. mirabilis L., and V* epipsila Led. Both of these 

 species belong to the section of Micropuccinia, and are notably 

 distinct from the other rusts on violets. A specimen of rust 

 collected by Marcus E. Jones at San Diego, Calif., in 1882, 

 was erroneously referred to the latter species, and distributed 

 by him as No. 3040. Puccinia cegra Grove is an autoecious 

 species found on the cultivated pansy and its close relatives. 

 It will probably be brought to America after a time through 

 commercial channels, as the rusts of asparagus, chrysanthe- 

 mum, carnation, hollyhock, and of some other cultivated plants 



