IMay 19, 1923 
Life History of Stripe Rust 
611 
An experiment also was conducted to compare the relative resistance 
to desiccation of urediniospores of several rusts. Puccinia graminis 
<ivenae Erikss. & Henn. on oats, Puccinia triticina Erikss. on wheat, 
Puccinia holcini Erikss. on Holcus lanatus L. and Puccinia glumarum 
iritici Erikss. and Henn. on wheat, were chosen. Leaves of the several 
hosts, heavily infected with the uredinial stage of the rusts, were collected 
and several portions of the infected leaves were placed in each of a num¬ 
ber of small glass vials which were then corked. Other infected leaves 
of each host were placed in three series of small paper herbarium packets. 
The three series of specimens in the paper packets were exposed to 
different sets of conditions. The first series was placed on a shelf in the 
open laboratory; the second, out of doors on a window ledge on the north 
side of the laboratory, and the third on a shelf in a culture room. The 
temperature and moisture conditions in this culture room were a little 
more constant, and both temperature and relative humidity were a 
little higher, than in the open laboratory. 
The glass vials containing infected leaves were divided into four groups. 
The first was placed on a shelf in the open laboratory, the second out of 
doors on a window ledge, the third in the culture room mentioned above, 
and the fourth in a small desiccator, the bottom of which was filled with 
water. This desiccator was kept in the culture room with the other 
collections. The vials in the desiccator were not corked. Table II gives 
the results of both these experiments. 
Table II .—Resistance of urediniospores of various rusts to desiccation when stored in 
paper packets and in glms vials, under different sets of conditions 
Kind of rust. 
Where exposed. 
• 
How kept. 
Date 
collected. 
Date of final 
coimt. 
Pinal 
germina¬ 
tion. 
Storage 
period. 
Puccinia graminis 
laboratory. 
Packets... 
Nov. 13,1918 
Peb. 4,1919 
Per cent. 
0 
Days. 
8a 
avenae. 
Do. 
Window ledge. 
...do. 
.do. 
.do.. 
12 
8a 
Do. 
Culture room. 
.. .do. 
.do. 
.do. 
0 
82 
Do. 
I^aboratory. 
Vials. 
.do. 
.do. 
0 
8a 
Do. 
Window ledge. 
... do. 
.,.. .do. 
.do. 
Trace. 
8a 
Do. 
Culture room. 
.. .do. 
.do. 
0 
8a 
Do. 
Desiccator. 
.. .do. 
.do. 
.do. 
0 
8a 
Puccinia glumarum 
tritici. 
Do. 
laboratory... 
Packets... 
lo 
8a 
Window ledge. 
.. .do. 
.do. 
* 0 
8a 
Do. 
Culture room. 
...do. 
.do. 
.do. 
lo 
82 
Do. 
Laboratory. 
Vials. 
.do. 
lo 
82 
Do. 
Window ledge. 
.. .do. 
.do. 
lo 
8a 
Do. 
Cultme room. 
...do. 
.do. 
.... .do. 
1 0 
8a 
Do. 
Desiccator.... 
...do. 
Dec. 3,1918 
Nov. 14,1918 
.do. 
.do... 
Trace. 
63 
81 
Puccinia triticina.... 
Laboratory. 
Packets... 
.do. 
0 
Do. 
Window ledge. 
.. .do. 
.do. 
3 
8x 
Do. 
Culture room...... 
.. .do. 
.do. 
.do. 
0 
81 
Do. 
Laboratory. 
Vials. 
.do. 
.do. 
3 
8x 
Do.. 
Window ledge. 
.. .do. 
.do. 
.do. 
0 
8x 
Do. 
Culture room. 
.. .do. 
.do. 
0 
8x 
Do. 
Desiccator. 
...do. 
.do. 
. .. . ; do. 
0 
81 
Purrinia hnlr.rni . 
Laboratory. 
Packets... 
.do. 
.do. 
3 
8x 
Do. 
Window ledge. 
.....do. 
5 
8x 
Do. 
Culture room. 
...do. 
.do... 
Trace. 
81 
Do. 
Laboratory. 
Vials. 
.do. 
.do. 
Trace. 
8x 
Do. 
Window ledge. 
Culture room. 
.. .do. 
.do. 
.do. 
Trace. 
81 
Do. 
.do. 
Trace. 
8x 
* Trace of germination in 20 days 
On January 8, 1919, urediniospores of P. glumarum tritici were taken 
from wheat leaves and placed on open slides and left under a bell jar in 
a culture room in the laboratory. The bell jar was raised slightly in 
