Jan. 1, 1925 
Composite Life History of Puccinia podophylli Schw. 73 
leaves is readily understandable when 
one has the fresh specimens in hand. 
These always occur on the thicker, 
fleshier parts of the sheaths. These 
parts mature more slowly than the 
margins, thus simulating the conditions 
obtaining in the longer-growing tissues 
of the leaf blade where aecia normally 
develop from this primary infection, as 
noted below. 
The infection on the sepals is not 
commonly observed because they soon 
drop off. If a search is made, however, 
at the right time, they can usually be 
found in considerable abundance on 
the ground among flowering stalks, and 
if infection is abundant in the patch on 
stems and sheath leaves these fallen 
sepals will almost invariably be covered 
with telia. Infected sepals still at¬ 
tached to the plant have, however, 
been found both at La Fayette and 
Ithaca (PI. 1, A). 
When basidiospore infection occurs 
on the blade of the leaf, aecial lesions 
almost invariably result. These show 
at first pycnia on the upper surface, fol¬ 
lowed shortly by the aecia below. It 
should be emphasized that the basidio- 
spores which cause this infection may 
result from the germination of either 
the early or late crop of teliospores of 
the previous season. 
The aecial lesions are rarely evident 
until after the teliospores on the sheath 
leaves, base of stem, and sepals have 
begun to mature. Fully developed 
aecia are seldom found earlier than a 
week after an abundance of mature 
teliospores appears on sheaths and 
stalks. It is obvious that these early 
telia could not have been produced 
from aecial infection. The delayed ap¬ 
pearance of the aecia is perhaps due 
to the slower development of the fungus 
in the less rapidly maturing tissues of 
the leaf blade. 
As the aecial lesions begin to mature, 
that is, when the cups are open and the 
spores are being discharged, one often 
finds, usually on the upper surface, 
about the margins of these lesions or 
more commonly on any larger veins 
wdiich may be included in the lesion and 
even in the center of the spot among 
the pycnia, a rather abundant produc¬ 
tion of telial sori along with more or 
less development of epiphyllous aecia 
(Pis. 2 and 3). These telia are like 
those developed on sheath and stem and 
are certainly developed on the same 
mycelium as the aecia. A careful study 
made by one of the writers (Jackson) 
of the sori in such lesions has revealed 
the fact that occasionally a greater or 
less production of chains of aeciospores 
may be found in these telial sori. In 
13949—25f-6 
similar situations aecia may occasion¬ 
ally be found with a few teliospores in 
the margin. In one specimen studied 
a sorus was found, one-half of which 
consisted of aeciospore chains and one- 
half of teliospores. 
Occasionally aecial lesions may be 
found in which pycnia do not develop 
and quite commonly only a very few 
pycnia are found. When infection 
takes place on leaves which are rela¬ 
tively quite mature the number of 
telial sori formed may be greater than 
the number of aecia (PI. 3, A and B). 
In one instance noted in the culture 
results, telia accompanied by pycnia, 
but with no aecia present, resulted from 
basidiospore infection on the leaves. 
Such a condition exactly parallels the 
normal result when infection occurs on 
the sheaths and stems, and is compa¬ 
rable to the usual condition of a micro- 
Puccinia. 
It has been observed at Ithaca, 
N. Y. (Whetzel), that a very much 
smaller number of leaf blade infections 
resulting in aecia occur than of infec¬ 
tions on scale leaves and stems result¬ 
ing in telia. Patches of Podophyllum 
have often been noted in which the 
early crop of telia on sheaths and stems 
was almost universal, but in which no 
aecial lesions on the leaf blades devel¬ 
oped during the season. In that local¬ 
ity no cases have been observed where 
more than a small percentage of plants 
showed aecial infections. This, how¬ 
ever, is not the case at La Fayette, Ind. 
Aecial lesions on the leaves are usually 
found in considerable abundance in in¬ 
fected patches. It would be interest¬ 
ing to have data on this point from 
other sections of North America, par¬ 
ticularly from regions at the northern 
limit of the range of the host species. 
The aeciospores are scattered by the 
wind and cause infection of the sur¬ 
rounding expanded leaves of the Podo¬ 
phyllum plants. This infection is usu¬ 
ally very profuse and general, and after 
a period of ten days or two weeks angu¬ 
lar yellowish spots appear, on the under 
side of which are developed the grega¬ 
rious, pulverulent telia bearing the sec¬ 
ond or summer crop of teliospores 
(PI. 4, B). These mature and fall to 
the ground to mingle with those of the 
early crop, which have already been 
largely disseminated. 
Reference has repeatedly been made 
to the two crops of teliospores. Those 
which appear early in the season on the 
sheaths, stems, sepals, and in associa¬ 
tion with the aecia on the leaves form 
the first crop, and those which arise 
from the infection of aeciospores form 
the second crop. There is, however, 
