Reed—Infection Experiments. 
149 
inoculation. The mildew was present on the rye during the 
whole time, conidia being produced abundantly. On the other 
hand, not one of the seedlings of wheat, oats or barley became 
infected, although conidia from the rye must have fallen re¬ 
peatedly upon them. 
Spores from blue grass were also sown upon several grasses 
that had been experimented with by Marehal and with similar 
results. Seedlings of rye, wheat, oats, barley, II. jubatum, and 
B. mollis were used. The following table presents the results: 
Table II.— Conidia from Boa pratensis. 
Plants on which spores 
were sown. 
Total 
No. of 
experi¬ 
ments. 
Age of 
seed¬ 
lings. 
No. 
inocu¬ 
lated. 
Results. 
Blue 
grass. 
On inoc. 
seed¬ 
lings. 
On 
controls. 
No. of 
trials. 
No. 
suc¬ 
cessful. 
Secale cereale . 
12 
7-12 
28+ 
-? 
— 
5 
5 
Triticum vulgare . . 
9 
10-16 
28 
- 
- 
9 
7 
Arena sativa . 
9 
8-19 
29 
- 
- 
9 
8 
Hordeum vulgare . 
10 
8-16 
24 
- 
- 
10 
8 
Hordeum jubatum ..... 
6 
16-53 
17 
- 
- 
6 
6 
Bromus mollis . 
5 
30-40 
12 
— 
— 
5 
5 
The sign — indicates no infection; —indicates that in one experiment there was, ap¬ 
parently, infection, an account of which is given below. The belljar was left over the 
seedlings for 24 hours or 48 hours, or in many cases, during the whole course of the ex¬ 
periment. Three to five different kinds of grasses were placed under the same belljar, 
one of them always being blue grass; consequently in the table the record of the obser¬ 
vations on the blue grass is in several cases repeated. The actual number of experi¬ 
ments with blue grass recorded in the table is twenty-three. Only two were unsuccess¬ 
ful. 
All of these experiments were made by the bell jar method 
except four of those with rye which were made by placing rye 
leaves in a Petri dish. Control seedlings were kept in each ex¬ 
periment. No infection occurred except in one instance. In 
this case four rye leaves were placed in a Petri dish and two of 
them inoculated with spores from the blue grass. In the same 
dish two other rye leaves were inoculated with conidia from rye 
and two were kept as controls. When examined a week after 
inoculation all of the eight leaves had patches of mycelium with 
conidia. This infection was doubtless due to allowing some of 
the rye spores used for inoculating two of the leaves to fall on 
the other six. In none of the other eleven experiments in which 
rye was inoculated with conidia from blue grass did infection 
occur. 
