396 Report oF THE HortricuLTuRAL DEPARTMENT OF THB 
these varieties which was examined on June 26. The pollen of 
this vuriety is quite irregular in shape and size and only about 10 
per ct. show the regular self-fertile shape, although there are 
numerous others which approach it very closely. Its grains are 
considerably larger than those of average pollen. In 20 per ct. 
Sugar solution about 15 per ct. of this pollen germinated. None 
of the growths appeared healthy however or at least were not like 
those of completely self-fertile pollen. In normal self-fertile pollen 
the tubes formed on germination are approximately the same size 
throughout, but the tubes of Eaton varied in size at different 
points of their course, being restricted at one place and swollen 
and distorted at another. The tubes were fully as long as those 
of normal self-fertile pollen. Other varieties which Prof. Beach 
has determined as belonging to the same doubtful class are 

Fic. 1.—Grapre Potten at Dirrerent Stages or GrowTsH. 
1, A Grain which has just Budded; 2 and 3, More Advanced Stages of Growth 
Dracut Amber, Maxatawney, Faith, Geneva, Montefiore, Canon- 
icus, Oneida, Gold Dust and White Jewell. Pollen of these was 
tested as was also that of Red Trauminer, Red Veltliner and 
Chables sent by Dr. Tinker of Ohio. In each instance the per- 
centage of pollen which germinated did not vary widely from the 
percentage of self-fertile forms which the microscope showed that 
particular variety to contain. And it appears very certain that 
the capacity of the pollen for growth is in direct proportion to the 
number of self-fertile forms present and their conformity to the 
self-fertile type. Pollen of the different varieties of grapes varies 
considerably in size, but there is no apparent connection between 
the size and the germinating capacity. . 
These results seem to confirm those previously secured in the 
field in showing that one of the reasons why certain varieties of 
grapes are self sterile is a lack of viability or potency in the pollen 
