Arthur: Cultures of Uredineae in 1908 237 



1908, was sown July 22, on Lycopsis arvensis L. On July 31 a 

 few pycnia appeared, but owing to the imperfect growth of the 

 leaf no aecia followed. 



This rust has usually gone under the collective name of P. 

 rubigo-vera (DC.) Wint., which has been applied to most sub- 

 epidermal grass rusts not having strongly marked morphological 

 characters. The similar leaf-rust of wheat is clearly a distinct 

 species, judging from the failure of European investigators to 

 make it infect Lycopsis, from some morphological differences, and 

 from its different period for germination. Teliospores of the 

 leaf-rust from both wheat and rye were tested in the laboratory at 

 the same time by means of drop cultures, and while the rye rust 

 grew readily, the wheat rust showed no germination. 



This unequivocal, although scanty result, the first culture of the 

 kind to be made with American material, sets at rest any doubt 

 regarding the identity of the American and foreign leaf-rust on 

 rye. The writer is indebted to the kindness of Dr. P. Magnus, 

 of Berlin, Germany, and Dr. H. O. Juel, of Upsala, Sweden, for 

 seeds of Lycopsis from which plants were grown for the culture 

 work. 



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

 (Torr.) A. Gray, collected by the writer at Spirit Lake, Iowa, was 

 sown on Cicuta maculata April 6, and gave rise to pycnia April 

 14, and aecia April 23, both in abundance. 



13. Uromyces houstoniatus (Schw.) Sheldon. In the spring 

 of 1906 Dr. J. L. Sheldon observed a rust appearing on plants of 

 Sisyrinchium gramineum Curtis (S. graminoides Bickn.), grow- 

 ing in contact with plants of Houstonia caerulea bearing Aeci- 

 dium hoastoniatum Schw. The rust on Sisyrinchium proved to 

 be Uromyces Murrillii Ricker, until then only once collected, at 

 the type locality in Maine. Dr. Sheldon has since made further 

 studies in the field, and also convincing inoculations, 23 and at the 

 same time supplied ample material for repeating his results. The 

 methods used for other species, however, have not proved avail- 

 able for this one, whose teliospores do not enter a resting condi- 

 tion, but germinate in the sorus as soon as mature. It is the only 



22 For previous cultures see Jour. Myc. 13: 199. 1907; and 14: 17. 1908. 



23 Torreya 6: 249. 1906; and 9: 54. 1909. 



