253 



Arthur: Cultures of Uredineae in 1^5 . 129 



grass rusts has shown the probability that this form, usually re- 

 ported under the name P. rubigo-vera, is a part of the compre- 

 hensive species, P. Agropyri, with aecia on different Ranuncula- 

 ceous hosts, forming well defined races. 7 



6. Uromyces Scirpi (Cast.) Burr., on Scirpus fluviatilis 

 (Torr.) A. Gray, sent by Dr. J. F. Brenckle from Kalmbach Lake, 

 Lamoure Co., N. Dak., was sown March 26 on Slum cicntae folium 

 and Hydrocotyle australe, and again May 19 on other plants of 

 the same two species, without infection. The species apparently 

 is made up of races, a study of which was the aim in this attempt 

 at cultures. 8 



7. Uromyces Archerianus Arth. & Fromme, on Chloris ele- 

 gans H. B. K., collected Nov. 12, 1914, and again Feb. 7, 1915, 

 by Mr. W. A. Archer, at Mesilla Park, N. Mex., was sown April 

 15, each collection on a different plant of Chenopodium album, 

 with no infection. This new species of rust was discovered in 

 abundance upon the campus of the New Mexico Agricultural 

 College, with no distinctive aecia in the vicinity. Because of its 

 morphological resemblance to Uromyces Peckianus, it was tried 

 upon Chenopodium. 



8. Aecidium Iridis Ger., on Iris versicolor L., from the Ren- 

 wick Swamp, Ithaca, N. Y., was sent by Mr. J. L. Weimer in 

 abundance and in excellent condition, and on July 1, the third day 

 after collection, was sown on a large and especially thrifty plant 

 of the same species of Iris, but gave no infection. A test of the 

 spores showed that seventy-five to ninety per cent, were in ger- 

 minating condition. Field observations have given little or no 

 grounds for considering this rust autoecious, and the present trial 

 further emphasizes this view. However, up to the present time 

 no one has detected a probable alternate host. 



Successful cultures supplementing previous work. The 

 facts derived by growing the following species of rusts supple- 

 ment in a variety of ways the facts obtained from previous cul- 

 tures in this series from cultures recorded by other American 



7 For previous attempts at cultures see Mycol. 2: 219. 19 10. 



8 For previous culture work see Jour. Myc. 13: 199. 1907; 14: 17. 1908; 

 Mycol. 1:237. 1909; and 7:83. 1915. 



