42 Research Bulletin No. 1 
Table 7. — Influence of lactic acid. 
February 12 
February 19 
February 26 
April 3 
April 4 
April 8 
Agar lactic 
acid. 
Culture 
started. 
lxl cm., yel- 
low, slimy. 
1 5 x 1.5 c m., 
yellow, slimy 
4x4 cm., ex 
ceeding ly 
pink. 
6x6 cm., very 
pink. 
9.5x9.5 cm., 
very pink. 
Table 8. — Influence of low temperature. 
Temperature 
April 1 
April 27 
April 28 
May 1 
May 8 
1° C 
Culture started. 
Culture started. 
Culture started. 
Removed to' Slight growth. 
temperature 
3.3° C. No 
growth. 
Removed to No growth. 
temperature 
3.3° C. No 
growth. 
Removed to No growth. 
temperature 
3.3° C. No 
growth. 
Removed to 
temperature 
22° C. 
Removed to 
temperature 
22° C. 
Removed to 
temperature 
22° C. 
Good growth. 
Good growth. 
9.5x9.5 cm., 
pink and 
fluffy. 
-3.9° C 
-22° C 
HUMIDITY. 
The fungus grows best under moist conditions and it is 
apparent that in most cases the supply of moisture is the de- 
termining factor for infection. 
COLOR. 
The color studies were carried on with cultures grown on 
glucose agar and on potato plugs. In general, the color produced 
on potato plugs is much more constant than that produced on 
agar. The general appearance of a colony on agar may show 
great variation, at times on whole plates and at times only in 
isolated parts of the same plate. This is undoubtedly due to 
variation in the condition of the media, to moisture variation, 
and the like. 
The cultures were grown in diffuse light, in the dark, at high 
and low temperatures, and in analyzed light. The cultures were 
on agar plates, on potato plugs, and on beef broth. Flask cultures 
on one per cent glucose and on synthetic media, in tap water and 
in distilled water were grown in the light and in the dark. 
Tables 6, 7 and 8 give in detail the observed colors which were 
noted on a series of cultures. Each series was run in triplicate. 
The general color of the fungus when two to three weeks old 
is a pale pink, sometimes grading over to a flesh pink, Repertoire 
de Coleurs, page 135, No. 3, and 136, No. 1 (PI. XXII). In the 
dark the cultures are more of a flesh pink color than pale pink. 
Whether the blue or red rays are shut out seems to be imma 
