Oct;-l, 1925 
Sclerotinia Species Causing Decay of Vegetables 
613 
spores. In fact, the only difference seems to be in the germinating 
power. The bodies which germinate are called spores tod those that 
do not germinate, or have never been observed to germinate, are 
called spermatia, or gonidia. 
In 1918 Brierley (8) was successful in germinating the small gonidia 
or microconidia or Botrytis cinerea . He found that these microconidia 
germinated in form 24 to 48 hours at 17° to 23° C. when placed in 
water or a nutrient medium. In water the growth soon stopped, 
but in nutrient media it continued until a normal Botrytis growth was 
obtained. It was concluded, therefore, that the microconidia were 
a normal developmental stage in the life history of Botrytis cinerea. 
After studying the conditions governing microconidial formation, 
Brierley considered the age of the fungus to be the chief determining 
factor. With few exceptions, the microconidia were not fpund in 
cultures less than 30 days old. The amount of available food seemed 
to be next in importance, since it influenced the quantity but not the 
kind of spore production. Light, moisture, and temperature ap¬ 
parently had no particular influence upon this type of spore forma- 
tion. 
The microconidia of the genus Sclerotinia are produced in various 
ways. Short, lateral branches arising from the vegetative mycelium 
or tips of the normal hyphae may produce these sporelike bodies in 
great abundance (pi. 4, K, L, ana M). Apparently Sclerotinia can 
produce microconidia at all stages in its life history when proper con¬ 
ditions are furnished. They have been found on the-surface of scle- 
rotia, on the disks of overmature apothecia which were held in a 
humid chamber, and on the tips of germ tubes where ascospor.es have 
germinated within the apothecium and in distilled water cultures 
(pi. 4, I and J). 
Microconidia which are of endogenous formation have also been 
noted in cultures grown in rutabaga broth (pi. 4, L). Sporogenous 
hyphae form witlnn some of the older vegetative cells and micro¬ 
conidia are cut off from the tip of the flask-shaped sterigmata which 
terminate these young hyphae. Vegetative cells have been found 
which contained large numbers of these small endoconidia. The 
manner of spore formation just described is practically identical with 
that figured and described by Beauverie and Guilliermond (.4, VV- 
281 , 815) for Botrytis cinerea when grown in sterile distilled water. 
The microconidia of the genus Sclerotinia are very similar to those 
of Botrytis, and are produced in extremely large numbers on media 
which are unsuitable for the vegetative growth of the fungus. Un¬ 
der such conditions, very scant ’mycelium is produced, and these 
small sporelike bodies are formed within a few days. On cultures of 
standard nutrient media, such as potato, bean, or oatmeal agar, 
most strains of Sclerotinia do not begin microconidial production 
until they are 20 to 30 days old. 
So far as observed, the amount of available food seems to be the 
chief factor in determining the time of microconidial production. 
Abundant food of a suitable kind stimulates vegetative growth 
greatly, and the microconidia are not produced until the fungus has 
apparently used up all or most of the available surface food. As 
noted above, this stage is reached in most test-tube cultures about 
the twentieth day. Microconidia are seldom found on the natural 
