60 MISSOURI BOTANICAL GARDEN. 
whatever in their germination and development being noted. 
Sclerotia when sectioned and placed on culture media are able 
to produce mycelium which produces normal conidia. 
Infection experiments: In no case was infection observed 
on healthy plants unless drops of water were present on the 
leaves; therefore, the plants were moistened with water just 
previous to inoculation. Plants sprayed with conidia in a 
nutrient solution like potato and prune broth produced in- 
fection in the majority of cases. Inoculated plants covered 
with bell jars gave almost a hundred per cent infection, the 
disease appearing in about three days. The progress of the 
disease was more rapid on cloudy days and when ventilation 
of the greenhouse was poor. Inoculations into wounds with 
spores produced the disease in all cases. 
Old lettuce plants, when dusted with dry conidia, were 
very slightly affected; when water was allowed to run into the 
lettuce head the percentage of infection was much greater. 
Lettuce plants sprayed with conidia in water or in a nutrient 
solution produced, as a rule, a heart rot. During the winter 
months lettuce was planted from time to time in the infected 
beds which, in a short time, became diseased. In addition to 
the distribution of the disease by conidia, the mycelium, which 
was found to some extent in the soil, was also capable of pro- 
ducing infection. 
With pepper and tomato seedlings no infection took place 
unless the spores were applied suspended in a nutrient solution 
and the plants covered with bell jars. In most cases the 
inoculated plants showed the presence of the fungus in three 
days, and within a week the plants collapsed. During the 
month of May, when the house was open and the days clear, 
all the above experiments were repeated, but negative results 
were obtained in most cases, showing that under conditions 
unfavorable to the fungus very little infection occurs. 
Experiments with the fruit of the tomato showed that in no 
case could the germ tube, produced by the conidia, penetrate 
the cuticle, even when they were submerged in a nutrient 
solution. When the cuticle was broken, the conidia 
