138 
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 Agfopyri 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 lo, instead of 6 
to 8 in P. Agropyri), sometimes accompanied by paraphyses, but 
more especially by the far broader teliospores (i8 to 34/4 wide, 
against 13-24 jx 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”. elyrnoides, 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 Hydrophyllum [capitatum] heavily infected with Aeci- 
dhini Hydrophylli. I think this rust has the alternate stage on 
Agropyron. I always find the Agropyron plant plentiful, and it 
is afifected 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 tencrum and Elymus 
virginicus. Uredinia began to show in abundance June 7, on the 
