July 1906] Better Classification of the Uredinales 
149 
REASONS FOR DESIRING A BETTER CLASSIFICATION 
OF THE UREDINALES.* ) 
BY J. C. ARTHUR. 
There are two especially prominent reasons for the consis¬ 
tent naming of the species of rusts, and for other plants as well. 
One is to be able to designate each particular kind as desired by 
using an authoritative name, and the other is to indicate the 
relationship which that kind holds to other kinds according to 
its recognized place in a natural system. If we examine the 
classification of the Uredinales now in use from these two stand¬ 
points, passing by for the present other points of view, many 
defects will be apparent, even to the verge of thorough con¬ 
fusion. 
The methods by which an authoritative name may be se¬ 
lected, when more than one has been in use, have been much dis¬ 
cussed of late and need not be taken up here. When the general 
rules of nomenclature are applied to the Uredinales, however, a 
complication arises in many cases due to the fact that some of 
the species possess partly or wholly independent phases of ex¬ 
istence during their life cycle; and these different phases have 
such nearly equally prominent characteristics that they were at 
first inevitably placed in separate genera, as if they were autono¬ 
mous organisms. When the different forms of a species are 
collected under one name, it would seem natural and logical that 
the several appellations previously in use for the different phases 
of the species should have consideration. Yet the view, that 
only names applied to the last or telial stage of the species are 
worthy of recognition, is held by many uredinologists. A discus¬ 
sion of this topic can not be taken up here, but it may be worth 
while to state the opinion of the writer that when the real signifi¬ 
cance of the several life phases of the rusts is better appreciated 
the opposition to a logical treatment of the Uredinales in con¬ 
formity with the treatment of other plants will largely, if not 
wholly disappear. In support of this opinion let it be noted that 
those who would discredit the nomenclatorial standing of the 
aecial phase are in the anomalous position of ignoring the sexual 
stage of the species, if we are to accept recent cytological studies, 
which in the case of other plants is considered the pivotal basis 
of classification. 
In passing to the second part of the subject it is worth bear¬ 
ing in mind that the desire for a stable nomenclature should 
never stand in the way of improvement in classification by segre¬ 
gation of genera to bring out more clearly the relationship of 
m rr 
* Read before the American Mycological Society, New Orleans Meet- 
January 1, 1906. 
