Jan. 1, 1925 
Composite Life History of Puccinia podophylli Schw. 75 
in addition to the difference in seasonal 
appearance, a noticeable difference in 
the character of these two sorts of telia, 
difficult to describe but easily recogniz¬ 
able when one has the specimens before 
him. In the early crop, the telia are 
usually somewhat larger, less definitely 
circular in outline and somewhat 
longer covered by the cinereous epi¬ 
dermis. They also cause a slight but 
distinct hypertrophy of the host tissue 
similar to that produced by the aecia. 
When on succulent tissue they also 
appear to have their origin much 
deeper in the tissues. This difference 
is perhaps best brought out by com¬ 
paring Plate 1, A and B with Plate 4, 
A and B. 
It seems probable that this differ¬ 
ence in type of sori is correlated with 
the fact that the early crop of telia on 
sheaths, stems, and sepals, as well as 
those which occur in association with 
the aecia, have a gametophytic origin, 
while the late crop which develops 
from aeciospore infection is sporo- 
phytic in origin. 
The writers have been unable to 
obtain any evidence either from observ¬ 
ation or cultures to show that this 
species possesses secondary or repeat¬ 
ing aecia. Cultures conducted both 
in the field and in the greenhouse under 
control conditions have shown that the 
aeciospores give rise to the summer crop 
of telia. 
SUMMARY OF LIFE HISTORY 
The teliospores of both the early and 
late crops are functionally and morpho¬ 
logically indistinguishable and the 
basidiospores developed on the promy¬ 
celium of either sort may, after 
overwintering, cause infection on any 
exposed portion of the Podophyllum 
plant. When infection takes place on 
the sheath leaves, stems, or sepals, 
telia are at once produced. They may 
or may not be accompanied by a few 
pycnia or aecia. When, on the other 
hand, infection takes place on the blade 
of the leaf, pycnia followed by aecia 
are developed. Aecia may develop 
without accompanying pycnia. Telia 
similar to tho^e on sheaths and stems 
may or may not accompany the aecia 
on the leaves, and when present develop 
from the same mycelium as the aecia. 
The late or summer crop of telia 
develops from aeciospore infection. 
There is no evidence of repeating aecia. 
GENERAL DISCUSSION 
It is evident from the above that the 
writers’ interpretation of the life history 
differs radically from that of Olive. 
It now becomes necessary to attempt 
to correlate this new interpretation 
with Olive’s cytological observations. 
The writers have at present no basis for 
criticizing these observations nor do 
they see any reason, for purposes of 
discussion, for not accepting them as 
matters of fact. 
It must be admitted, however, that 
in view of the experimental results 
recorded above, it would be highly 
desirable that the cytological situation 
in Puccinia podophylli be reinves¬ 
tigated. It is apparent that we are 
dealing with a rust showing consid¬ 
erable plasticity in its development 
since from basidiospore infection telio¬ 
spores are the first spore form produced 
under some conditions, while under 
others, pycnia followed by aecia occur. 
It will be recalled that Olive found 
a small amount of uninucleate mycelium 
with the developing telial sori on the 
sheaths and an abundance of such 
mycelium in lesions on the leaves, but 
that the aeciospores as well as the 
teliospores developed on a binucleate 
mycelium. No so-called sexual fusions 
were observed to take place at the base 
of the aecial cups. It was assumed that 
all the telia and aecia were formed on a 
perennial binucleate mycelium and the 
pycnia were formed on a perennial 
uninucleate mycelium. The aecia were 
then assumed to be secondary in nature 
and sexual fusions would not be 
expected. They were to be expected, 
according to this view, in the primary 
aecia which would originate from basidi¬ 
ospore infection. These Olive assumes 
he had not seen, and evidently con¬ 
sidered it doubtful whether they would 
be found to be present in the life 
history. 
In view of the evidence already 
presented it would hardly seem neces¬ 
sary to consider seriously the possibility 
of a systemic perennial mycelium in the 
case of this parasite. However, the 
paper by Olive has given this theory 
such general acceptance that it seems 
necessary to emphasize the fact that 
the writers have not been able to 
obtain the slightest evidence that the 
rust is in any sense perennial, or even 
systemic, in the host plant. 
According to the view of the writers, 
accepting the cytological findings of 
