BULLETIN OF THE BUSSEY INSTITUTION. 419 
acute, and with a short projecting point at the attached end. Their 
size is very variable, the smaller being .0085 mm. by .0125 mm. and 
the larger about .017 mm. by .038 mm. 
GERMINATION. — The germination of the conidia was studied by us 
in the beginning of October, when the fungus was in its prime. 
Leaves affected with the fungus were gathered in the afternoon, and 
allowed to remain under a moistened bell-glass during the night. In 
the morning, parts of the leaves where fresh conidia had grown during 
the night were cut out, and the conidia shaken into watch-glasses, or 
on to glass slides containing a few drops of water. In order to test 
the conditions of germination, some of the bell-glasses were placed in a 
light room, and others kept in the dark, and sowings were made at 
different hours of the day. ‘The result was uniformly the same, 
whether the conidia were in the dark or the light. Experiments in 
direct sunlight were, however, unsuccessful, as the sun’s rays heated the 
water to such an extent as to cause rapid evaporation of the neces- 
sarily small amount of water used. With relation to the time of day 
at which the sowing was made, germination took place in all cases ; 
but the conidia sown in the morning generally germinated somewhat 
more quickly and more abundantly than those sown in the afternoon. 
This might have been partly owing to the fact, that the conidia sown in 
the morning were in better condition, the result of a growth of four- 
teen or fifteen hours; while those sown in the afternoon were the 
conidia produced during only four or five hours of the forenoon. It 
was not possible to keep the conidia which were produced in the night 
until the afternoon, as they generally fell from their attachments in 
the morning, and began to germinate. In all cases, the germination 
took place with a surprising regularity. At the end of an hour, the 
conidia were slightly swollen and their contents had begun to segment, 
as shown in Plate III., Fig. 4, each segment having a light-colored 
nucleus. At the expiration of an hour and a quarter, the segments 
had resolved themselves into a number of oval bodies, which collected 
at the distal end of the conidia, and which, before long, succeeded in 
rupturing the cell wall and making their escape from the mother-cell. 
They passed out rather slowly, usually one at a time, and paused for 
a moment in front of the opening, where they remained as if not yet 
quite free from one another. In a short time each segment began to 
extricate itself from the common mass, moved more and more actively, 
