138 JJ6 Mycologia 



fusion in the application of this name. Not until within the pres- 

 ent year has it been possible to secure a clearly defined set of 

 characters with which to delimit the species, especially to distin- 

 guish it from Puccinia Agropyri E. & E., with which it often 

 grows, and which it resembles in gross appearance. It is now 

 found to be separable from P. Agropyri, by the slightly thinner- 

 walled urediniospores, having more pores (8 to io, instead of 6 

 to 8 in P. Agropyri), sometimes accompanied by paraphyses, but 

 more especially by the far broader teliospores (18 to 34 ju, wide, 

 against 13-24/* in the other species), which generally approximate 

 an oblong form with convex sides, in contrast with terete spores 

 usually with straight sides in P. Agropyri. 



The rust in question has often been labeled P. apocrypta E. & 

 T. The type of P. apocrypta was collected at Canon City, Colo., 

 August 21, 1887, and was recorded as on Asprella Hystrix. The 

 type collection is now in the herbarium of the Missouri Botanical 

 Garden, and has been carefully examined by a number of students 

 of the grasses. The specimen is scanty, and consists of leaves 

 only. It can not be the species of grass named, which does not 

 occur within the region. It seems most likely to be some species 

 of Sitanion possibly 5\ clymoides, a common species of the region 

 much resembling Hystrix. The rust is certainly P. Agropyri, 

 although the teliospores are rather broader than usual. The type 

 material of P. montancnsis, which is in the herbarium of the New 

 York Botanical Garden, has been examined and bears out the pub- 

 lished statement that it is on Elymus condensatus. It was col- 

 lected at Helena, Mont., July 25, 1891, by F. D. Kelsey. 



The fortunate observation which led to the elucidation of this 

 species was made by Mr. A. O. Garrett, of Salt Lake City, Utah, 

 who wrote on May 23, 1915: "I am sending by this mail some 

 leaves of Hydro phyllurn [capitatum] heavily infected with Aeci- 

 dium Hydrophylli. I think this rust has the alternate stage on 

 Agropyron. I always find the Agropyron plant plentiful, and it 

 is affected by the rust, wherever the Hydrophyllums grow." The 

 aecia on Hydrophyllum sent by Mr. Garrett came in good condi- 

 tion, and were sown May 28, on Agropyron tenerum and Elymus 

 virginicus. . Uredinia began to show in abundance June 7, on the 



