190 
Journal of Mycology 
[Vol. 12 
place of the genus Puccinia as now commonly used, rests upon a 
wholly different consideration, having to do fundamentally with 
the progressive evolution of the rusts, and not with adaptations. 
While .space does not permit the presentation of an argument suf¬ 
ficiently full to demonstrate this proposition and carry convic¬ 
tion, yet it may be pointed out that while the genus Dasyspora 
includes species, all of which have progressed in their evolu¬ 
tion to the stage where the aeciospores and urediniospores have 
been effectively suppressed from the life cycle, yet it includes 
both leptoforms and microforms, according to their adaptations to 
the requirements of the environment, some species exhibiting only 
one or the other adaptation, and some assuming either form, now 
one, now the other, in accordance with conditions affecting 
growth not yet made clear. In the same way autoecism and 
heteroecism are regarded as adaptations, and not as an evolution¬ 
ary development of generic rank. Having set up this principle, it 
becomes logical to separate Gallowaya from Coleosporium , 
Chrysomyxa from Melampsoropsis, Macalpinia from Uromyclad- 
ium, Dendroecia from Raven elia, Calliospora from Uro pyxis, 
Nyssopsora from Triphragmium, Telospora from Nigredo, etc. 
But it would be a wholly false impression to assume that this 
character of the suppression of spore forms is the only one sepa¬ 
rating the genus from the others of its group. It is the most 
prominent and the most easily stated, but in most cases will be 
found associated with other characters of acceptable value. 
There is another argument beside that based upon phylogeny 
for the separation of species into genera as indicated above, and 
that is, convenience. It will lead, it is believed, to a better recog¬ 
nition of the various forms that go to make up each species, par¬ 
ticularly valuable in the exploration of new or old floral regions, 
and also will permit clearer concepts in discussions relating to 
phylogeny, ecology, distribution, cytology, and a host of other 
problems. Even if there are those who do not admit the validity 
of the claim for true generic characters underlying the genera in 
question, they must accord the right to establish among the rusts, a 
group of organisms where parasitism of the most obligatory 
nature has constantly reduced the number of chances for dis¬ 
playing diversified characters, while increasing the physiological 
sensitiveness of the fungus to variations in the host, genera of 
this kind so long as they are as useful for the genuine increase of 
knowledge as have been the genera Puccinia and Uromyces, 
which are separated upon no better grounds than those advocated 
for the genera in question, if in fact as good, and no one, so 
far as the writer knows, has seriously insisted upon merging 
these two genera. 
A few words may be said in regard to the nomenclature. 
The generic names have been chosen, such as are not new, in 
accordance with the American doctrine of types as applied in 
