374 ARTHUR: NEW SPECIES OF UREDINEAE 
to one another on the leaves of the host that is usual in 
autoecious species. The following specimens also belong here: 
on A. brevistylum S. Wats., Big Horn Mts., Wyo., August 
1898, T. A. Williams & D. Griffiths, 111; Ten Sleep Lakes, Big 
Horn Co., Wyo., July 30, 1901, Leslie N. Goodding 422, II & III; 
Hot Sulphur Springs, Colo., 2340 m. alt., July 24, 1907, E. Bethel, 
II & III; on A. validum S. Wats., Pine Forest Mts., Nev., July 
1901, Griffiths & Morris, 11 & II] (Griff., West Am. Fungi 397); and 
intermixed with Puccinia Blasdalei D. &. H. on A. acuminatum 
Hook., Farmington Canyon, Davis Co., Utah, June 3, 1904, 1700 
m. alt., A. O. Garrett, III (Garrett, Fungi Utahenses 83). 
This species is most easily confused with Uromyces aureus D. 
& H., but that species, which is known only from a single collection 
made in California on Allium validum in 1892, has larger spores, 
entire absence of urediniospores, and a different disposition of 
aecia and telia on the leaf, the aecia closely surrounding the groups 
of telia, and both seemingly arising from the same mycelium. 
The type collection was first distributed under the name Uromy- 
ces bicolor E. & E., and other Wyoming specimens under the 
name U. aterrimus D. & H., which is a synonym of the preceding, 
but that species, generally at lower levels, has strictly subepidermal 
telia with well developed stromata, and urediniospores with a 
larger number of especially distinct pores. In its urediniospore 
it is similar to the European U. ambiguus (DC.) Fckl., but that 
species has permanently covered telia, and obovate teliospores. 
The Allium species of Puccinia are much given to the pro- 
duction of mesospores, in some sori even to the exclusion of the 
two-celled spores, but these can be distinguished from the present 
species by morphological characters. The collection distributed 
in Garett’s Fungi Utahenses, 83, consists of a mixture of U. 
_aemulus and P. Blasdalei D. & H. The telia are quite readily 
separated under a hand lens. Those of the Uromyces are grayish 
and inclined to be naked, while those of the Puctinia are quite 
black and closely covered. The mesospores of the latter have a 
semihyaline, thickened apex and are not globose. 
There has been much confusion in determining the American 
Allium rusts. Most collections are not provided with either 
flowers or bulbs, which are usually needed to name the hosts, but 
