A PARASITIC BOTRYTIS ON PEPPER AND LETTUCE. 57 
30°C. the mycelium grew moderately well, covering the sur- 
face in about three weeks. At the end of five weeks the 
experiment was discontinued, the mycelium remaining 
sterile. At ordinary room temperature the best growth took 
place; numerous sclerotia were formed, with the conidia 
developing, as a rule, after the sclerotia had, for the most 
part, matured. Growth was somewhat retarded, but after 
two weeks the mycelium completely covered the surface of 
the plate and sclerotia developed. Only in one of the cul- 
tures were conidia produced, the abundant mycelium giving 
rise only to sclerotia. 
From these experiments we may conclude that the fungus 
is unable to live long at a temperature of 37°C.; that at a 
temperature of 15°C. and 30°C. growth of the mycelium 
takes place normally, but not rapidly; a few sclerotia and, 
in some cultures, conidia are produced. The optimum, 
then, for rapid normal growth of the mycelium lies in the 
neighborhood of 20°C. 
What the significance of the non-production of conidia at 
certain temperatures is we are unable to explain. Beauverie 
(3), working on the polymorphism of Botrytis, obtained a 
similar result. He succeeded in getting a strain of the fungus 
which, when kept under certain conditions (mainly of tem- 
perature and moisture), never formed conidia. He found 
that after controlling these factors for a long time the fungus 
was unable to return to its former state. When the above 
conditions were varied it always remained sterile. 
Light and darkness: No appreciable difference was noted 
between the cultures grown in light and in darkness, except 
that the latter favored the non-production of conidia and the 
formation of a large number of the striated pseudo-sclerotia, 
while light favored the greater development of conidia. The 
sclerotia appeared to grow equally well in light and in dark- 
ness. , 
Longevity: The length of life of the mycelium varies but 
little, and in no case does it extend beyond two months. The 
conidia, on the other hand, are much longer-lived, since even 
after six months they are capable of germinating and pro- 
