Sept. 1906 ] A New Classification of the Uredinales 
189 
mycelium, it may safely be assumed that no uredinia belong to 
the life-cycle. Furthermore, it rarely or never happens that 
teliospores of the Uromyces-Puccinia type, germinating imme¬ 
diately upon maturity, belong to genera with other spore forms 
in the life cycle, excepting the largely tropical genera of Erio- 
sporangiam and Argotelium. 
Short cuts are also available in other directions. All gra¬ 
mineous and cyperaceous hosts bear rusts that may be assumed 
to possess all spore forms and are heteroecious, only one excep¬ 
tion being positively known at present. Rusts on rosaceous hosts 
largely belong to the genera of the sub-family Phragmidiatae, 
and on leguminous hosts largely to genera of the sub-families 
Raveneliatae and Uropyxidatae, and so on. 
But probably one of the most efficient short cuts, and a 
wholly legitimate one, owing to the phylogenetically intimate re¬ 
lation of fungus and host among the rusts, will eventually be 
the consultation of a host index. In the present chaotic condi¬ 
tion of taxonomic literature in this group no very comprehen¬ 
sive indexes exist, but they are likely to be provided in the early 
future. By this means it can be readily ascertained what species 
have been recognized upon the host in question, and from this 
list, usually small, not much difficulty will be experienced as a 
rule in locating the particular rust. 
Another difficulty in using the new system will probably be 
felt in the much larger number of genera to be recognized. Some 
of these genera have been long known, but only partially ac¬ 
cepted, and consequently little used, like Pileolaria, Uropyxis, 
Trachyspora, Gymnoconia, Kuehneola, Eriosporangium, and 
Dasyspora Not being well understood, they have remained mono- 
typic, or with only a few species each, although every one of these 
genera really contains more than one and some many species. 
Other genera have been established to recieve species which show 
relationships quite different from those usually assumed for them. 
Thus, Transzschelia and its closely associated genera have many 
characters showing their close relationship with the Ravenelia 
group, and have only superficial resemblances to the Puccinia- 
Uromyces group in which they have heretofore been submerged. 
But probably the most striking innovation is the placing of like 
species under different genera, according as they possess all or 
part of the spore forms in their life cycle. At first thought 
this seems to be an appropriation of the Schroeterian biological 
classes, into which every genus was considered to be potentially 
divisible, i. e., heteroforms, auteuforms, opsisforms, brachyforms, 
hemiforms, microforms, and leptoforms, and calling these classes 
genera. But in reality the basis of the segregates which I have 
recognized, for example, Dasvspora with teliospores, Bullaria, 
with urediniospores and teliospores, Allodus with aeciospores and 
teliospores, and Dicaeoma with all spore forms which take the 
