NOTES ON PLUM CULT UR PL 
25 
helpful to the planter, and would become more valuable as 
the number of years over which observations extend, in- 
creased. 
TO WHAT DEGREE ARE PLUMS SELF-FERTILE. 
The following tests to determine self-fertility were under- 
'taken last spring, the work being in charge of my assistant, 
Mr. J. H. Cowan, who was assisted by one of our students. 
The preliminary work of covering the flowers was perform- 
ed on April 30th, with the exception that the flower clusters 
on one variety, Missouri Apricot, were covered May 7. 
Grocer’s paper bags were used and securely tied. Such 
flowers as were open, or partially open, were removed 
before covering, and are not counted. Approximately one 
half of the clusters were hand-pollinated, the other half 
being left to themselves. The hand-pollinated set embraced 
43 clusters, containing 629 flowers and represented 40 vari- 
eties. The stigmas of all flowers were dusted with pollen, 
either from the same flower, or from other flowers of the 
same cluster. This work was performed on the dates as tab- 
ulated, May 14-18 inclusive. The pistils were at this time 
in good condition, the stigmas appreciably viscid. The 
pollen was also in good condition, and the stigmas were 
copiously covered. 
The examination June 6 showed 1 13 apparently well 
formed fruits, and 105 imperfect fruits, those that showed 
some development of the ovar^, but did not appear to be 
well fertilized. In other words it appeared on June 6 that 
17.94 per cent, of the flowers had produced good fruits, and 
16.69 per cent, had set imperfect fruits. At the final exam- 
ination June 23 there remained 6 fruits representing a frac- 
tion less than i per cent, of the flowers pollinated. 
In the following tabulation the number of flowers treated 
is given for each variety, together with the number of fruits 
formed, and also the estimated stand of fruit on the trees. 
