886 Report OF THE HORTICULTURAL DEPARTMENT OF THB 
tinguish it. On another part of the tree some open blossoms 
which had not been sprayed were tagged for comparison with the 
sprayed blossoms. 
A Jefferies apple tree which showed its first bloom May 138, 
also had a part of its blossoms sprayed May 14. They were 
marked after the same plan which was followed with the Hurl- 
but and unsprayed blossoms were likewise tagged for comparison. 
Later observations showed that out of 42 sprayed Hurlbut 
blossoms which were known to have been hit by the spray 36, or 
86 per ct., failed to set fruit, while out of 31 corresponding 
blossoms which were not sprayed only 5, or but 16 per ct. failed to 
set fruit. Out of 11 Jefferies blossoms known to have been hit 
by the spray 8, or 73 per ct. set no fruit while out of 10 corre- 
sponding unsprayed blossoms only 3, or 30 per ct., failed to set 
fruit. None of the blossoms which were seen with spray mix- 
ture on the stigmatic surface of the pistils set fruit on either 
tree. 
The Baldwin and R. I. Greening trees which were used in this 
test were sprayed a week later, on May 21, using the same kind 
of spray mixture as before. It was difficult at this time to find 
branches of the tree which were, properly speaking, in full bloom 
because in so many cases the center flower of the cluster had 
already gone out of bloom. The center blossom of the cluster 
opens first and naturally may be expected to drop its petals before 
the other flowers of the cluster do. Some branches were finally 
found on the northeast side of the tree on which most of the 
clusters were still, strictly speaking, in full bloom, although, in 
the blossoms on two of the trees as the sequel shows, the pollen 
tubes had doubtless in the majority of cases already entered the 
style and passed beyond the reach of the poisonous influence of 
the spray mixture. After they had been sprayed some of the 
blossoms were examined and tagged in the way already described 
for the Hurlbut blossoms. Corresponding unsprayed blossoms 
were likewise labeled. Later observations showed that none of .~ 
of the blossoms which had the stigmatic surfaces plainly covered 
by the spray mixture set fruit. Out of 45 R. I. Greening blossoms 
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