= 
54 MISSOURI BOTANICAL GARDEN. 
top, which are less easily affected. In the later stages, conidia 
arise from the diseased areas. This Botrytis did not appear 
to be typical B. cinerea, because of its low manner of growth 
and the short branching conidiophores. However, when the 
fungus was obtained in pure culture and grown on suitable 
media, sclerotia were produced which showed that it was 
Botrytis cinerea. It also resembles in many ways the Botrytis 
described by Ward, which is in all probability a form of B. 
cvnered. 
During the month of May the Botrytis in the greenhouse, 
where the infection experiments were tried, was in some man- 
ner carried over to a neighboring house given over to the 
growing of garden beans, where, under conditions favorable 
to its development, it attacked the flowers and pods. The 
spore germinating on the flowers developed into a parasite, 
and the diseased flowers falling on the pods rapidly spread 
the disease. Several times during the spring Botrytis has 
been observed on plants killed by a light frost; here conidia 
were formed abundantly, but no sclerotia. 
PHYSIOLOGY. 
The fungus was obtained in pure culture by plating on 
potato agar. From a rather abundant growth of mycelium 
conidia were transferred to suitable media in test tubes. All 
subsequent cultures from lettuce and other sources were 
secured in the same manner. The fungus has been kept in 
pure culture since October, 1911, and its behavior on various 
media studied to ascertain the one most suitable to employ in 
experimental work. All cultures, unless otherwise stated, 
were grown at room temperature. 
Media: Upon lettuce leaves in Petri dishes, a rather vigor- 
ous mycelium, with many conidia and few sclerotia, was 
produced. 
In lettuce broth, mycelium developed abundantly, but no 
conidia or sclerotia were produced until the culture was rather 
old and the mycelium had formed a thick mat on the surface. 
In no case were conidia developed in the liquid itself. 
