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609 ReEporT OF THE HORTICULTURIST OF THE 
the pistil of the same flower. In either case the remedy would 
be the same, namely, the growing of vines of other varieties in 
proximity to these self-sterile kinds, to supply them with pollen of 
a congenial kind at the proper season. Fig. 19 illustrates the 
result of a lack of proper pollination in two clusters of the 
Lindley grape. 
The self-fertility of several varieties was tested by 
inclosing clusters of grapes in paper bags before the 
blossoms opened, and allowing them to remain covered 
until the blossoming period had passed. This effectually shut out 
foreign pollen and made it possible for the stigmas to be pollenized 
only by stamens of the same flower or of the same cluster. In 
this way it was found that several of the varieties experimented 
with are unable to set fruit unless furnished with other pollen 
than that produced by themselves; other varieties set fruit imper- 
fectly when supplied only with their own pollen, while still others 
treated in the same way produce perfect or nearly perfect clusters 
of fruit. 
Good sized clusters of blossoms were selected for the experi- 
ments whenever practicable, and it is estimated that the average 
number of flowers per cluster was more than fifty, so that from 
100 to 500 blossoms were used for each variety under experiment. 
The results of these tests aré given below. In order to indicate 
the degree of self-fertility, as shown by these experiments, the 
varities are designated as “fully self-fertile,” “partly self-fertile,” 
“pollen self-irritant,” or “pollen impotent,” as the case may be. 
With those which are designated as “fully self-fertile,’ from 
97 per cent to 100 per cent of the blossoms developed into fruit. 
With those designated as “partly self-fertile,’ the number of 
flowers which produced fully developed fruit varied from none 
to 97 per cent. . 
Those varieties which set fruit that soon dropped or that per- 
sisted throughout the season in a dwarfed and abortive state, are 
designated as having “ pollen self-irritant,” meaning that in these 
cases self-pollination incites a slight growth of the ovary, but is 
unable to cause the development of perfect fruit. 


