722 
Journal of Agricultural Research 
Vol. V, No. 16 
Table I. —Effect of light: Tests with filter paper (readings in g days ) 1 
Conditions. 
Number of 
pycnidia. 
Growth. 
Filter paper in light. 
+ 
H — b 
++ 2 
Filter paper in dark. 
1 In tables where a single plus symbol (+) is contrasted with the negative sign (—), presence or absence 
is meant. Where a series of readings is given and several plus symbols are used with reference to pycnidia 
production, they give the average of two and at times of four readings, as follows: + = i to io pycnidia; 
++ = io to 25; +++ — 25 to 50; +++ + .= 100. As applied to growth the same plus symbols mean, re¬ 
spectively, scant, fair, good, abundant growth. 
a A trifle stronger than above. 
The cultures which had been in the dark were exposed to light about an 
hour at a time, when the reading was made. A second observation after 
27 days showed the following result: 
Table II. —Effect of light: Tests with filter paper (readings in 27 days) 
Conditions. 
Number of 
pycnidia. 
Growth, 
Filter paper in light. 
+ 
Sclerotia. 
H — h 
+++ 
Filter paper in dark (except one hour’s exposure). 
These bodies, called provisionally “sclerotia,” when examined under 
the microscope were found to be minute brown bodies about one-tenth 
the size of the ordinary pycnidium and consisted of a firm, solid pseudo¬ 
parenchyma. 
In no case was any suggestion of chamber formation noticed; nor 
were any spores found. It is noteworthy that the growth after this 
longer period could be seen to be stronger in the dark than in the light. 
As part of the same experiment, a drop of some sterile M/i chemical 
was added as indicated to a number of similar filter-paper cones. The 
results are as follows: 
Table III. —Effect of light: Pycnidium formation on filter paper plus various chemicals 
Chemical. 
9 days. 
27 days. 
40 days. 
Light. 
Dark. 
Light. 
Dark. 
Light. 
Dark. 
Filter paper + approxi¬ 
mately 1/20 C. C. 01 — 
Calcium nitrate , 
Ca(N 0 3 ) 2 M/i . 
+ 
+ 
Sclerotia. 
.+ 
Sclerotia. 
Potassium acid phos¬ 
phate, KH 2 P 0 4 M/i . . 
+ 
+ 
— 
+ 
+ 
Potassium nitrate, 
KN 0 3 M/i .. 
+ 
_ 
+ 
+ 
Sclerotia. 
Calcium acid phos¬ 
phate, Ca(H 2 P 0 4 ) 2 
M/i . 
+ 
- 
+ 
- 
+ 
- 
