New York AGRIcuLTURAL EXPERIMENT STATION. 519 
eree of self-fertility which they have shown in these tests, into 
four lists which are given in full in the body of the report. Class 1 
includes self-fertile varieties having perfect clusters or clusters 
varying from perfect to somewhat loose. Class 2 includes self- 
fertile varieties having clusters loose but marketable. Class 3 in- 
cludes varieties which are so imperfectly self-fertile that the self- 
fertilized clusters are generally too loose to be marketable. Class 4 
includes the self-sterile varieties. Whenever cross-pollination has 
been prevented these have developed no fruit. 
The varieties named in Classes 1 and 2 form marketable clus- 
ters from self-pollinated blossoms and may be planted alone. ‘Those 
which are named in Classes 3 and 4 should be planted near other 
varieties which bloom at the same time because when cross-polli- 
nation is prevented they either produce no fruit or the clusters 
which develop are too loose to be marketable. Lists showing the 
period of blooming of most of these varieties are given in this 
report. 
The method of testing grapes as to self-fertility by covering the 
clusters during the blooming season to prevent cross-pollination is 
certainly reliable with varieties which have long stamens, and 
apparently so with all other varieties. 
Short or recurved stamens are always found associated with 
complete or nearly complete self-sterility. 
Long stamens are not a sure indication of self-fertility because 
some varieties which have long stamens are self-sterile. 
The most satisfactory explanation of the self-sterility which 
exists among grapes appears to be that there is a lack of affinity, in 
the self-sterile varieties, between the pollen and the pistils of the 
same variety. | 
HISTORY OF INVESTIGATIONS. 
Investigations concerning the self-fertility of grapes were begun 
at this Station in 1892 and the work has been continued till 
the present time. These tests have included twelve American 
species, together with many of their hybrids with each other and 
