Jan. 1, 1925 
Composite Life History of Puccinia podophylli Schw. 69 
of Podophyllum leaves which bore the 
second, or summer crop, of teliospores 
in abundance, put them between two 
sheets of window screen and placed 
this over one end of the established 
rust-free planting in his yard. This 
plot had developed so that it was 
about 8 feet long and rather narrow. 
The screen packet was about 12 by 18 
inches. During the fall and winter 
the Podophyllum leaves in the screen 
rotted and the spores fell with the 
debris through the meshes upon the 
surface of the soil. Early in the spring 
of 1917 the empty screen was removed 
and careful observations were made on 
all the plants in the plot at frequent 
intervals as they developed. Telia 
soon appeared on the sheath leaves and 
stems of nearly all the plants which 
came up in the area covered by the 
screen packet. No rust appeared on 
plants elsewhere in the bed during the 
entire season. A seedling in the infect¬ 
ed area also developed aecial lesions on 
the leaf blade in the spring of 1917. 
Two nearby seedlings showed telia only 
on the stems. One of these seedlings 
stood directly under that bearing aecia 
and when all three were removed on 
June 4, 1917, it showed the whitish 
lesions of the developing but unopened 
summer telia. However, no summer 
crop of telia appeared on any of the 
other plants in the patch during 1917. 
In 1918, while leaf sheath and stem 
lesions bearing the early telia were 
common, only a single plant developed 
an aecial lesion. This was allowed to 
remain, and later nearly every leaf blade 
in the patch showed a more or less 
abundant development of the summer 
telia. Since that time this patch of 
plants has been rusted more or less 
each year, all stages of the rust appear¬ 
ing in the manner usual for this species. 
This experiment, while not in itself 
conclusive, strongly suggests that the 
interpretations of the life history made 
by Olive are not in accord with the 
facts. It would appear from this 
experiment that the infection on the 
sheaths and stems, resulting in the 
early crop of telia, arose directly from 
the basidiospores developed from the 
late crop of teliospores which were 
used as the inoculum and that these 
teliospores were responsible also for 
infection on the seedling leaves, result¬ 
ing in pycnia and aecia. Since the 
aecial-bearing seedling was removed 
along with the seedling showing the 
initial stages of the summer telia, and 
since no other plant in the patch showed 
summer telia during 1917, it would fur¬ 
ther appear that the spring crop of 
teliospores was responsible the next 
season for the development not only 
of another crop of early teliospores on 
sheath and stem but also for pycnia and 
aecia later. 
EXPERIMENTS AT LA FAYETTE, IND., 
1917-1921 
Since this experiment was conducted 
entirely out of doors and the usual 
objections to such experiments would 
naturally arise, it was decided to repeat 
the work with variations, in part at 
least under controlled conditions, and 
to eonduct this work in connection with 
the rust investigations under way at 
the Purdue University Agricultural, 
Experiment Station at La Fayette, Ind. 
Experiment 1.—During the sum¬ 
mer of 1917 patches of Podophyllum 
were located in the woods, some of 
which were heavily rusted and some of 
which showed no rust. An equal 
number of plants, about 25, were dug 
in November from each of two plots, 
one of which was rusted and the other 
not. The rhizomes were very care¬ 
fully washed and cleaned of all soil or 
dead parts and planted in a single row 
in a vegetable garden (Jackson’s), 
with a stake dividing the two lots. A 
frame 18 inches by 48 inches made of 
boards 4 inches wide was placed on the 
ground in the middle of the row in such 
a position as to include 5 plants from 
the rusted patch and 5 from the one 
which showed no rust. A peck or less 
of surface soil and debris taken from a 
patch of Podophyllum which had been 
heavily rusted during the previous 
summer was evenly spread over the 
soil in this frame. No protection was 
given the plants during the winter. 
In the spring of 1918 all 10 plants 
in the frame showed the early telia 
on the bud sheaths or stems and later 
about half of them showed pycnia and 
aecia in fair abundance on the blades 
of the leaves. No infection of any 
sort occurred on the other 40 plants 
at either end of the frame. The 
experiment was not continued since 
the ground was needed for other 
purposes. 
Were the rust perennial in the 
rhizomes some of the plants outside 
the frame which had been dug from 
the rusted patch should have been 
rusted. The infection on the plants 
in the frame presumably resulted from 
the teliospores present in the top soil 
used as a mulch. 
Experiment 2.—In November, 1917, 
about 50 rhizomes dug from a patch 
of Podophyllum which showed heavy 
infection on nearly every plant during 
the spring were thoroughly washed. 
