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HORTICULTURAL SOCIETY OF NEW YORK. 



poses. At the same time that these observations were being made the pollen 

 itself was being studied to determine, if possible, the exact status of the 

 pollen itself as a factor bearing on fertilization. This part of the work was 

 wholly of a laboratory and microscopic nature, the only portion which took 

 place in the field being the gathering of the blossoms. For this purpose the 

 following list of varieties was selected for examination and comparison : 



PERCENTAGE SELF-FERTILE VARIETIES. PERCENTAGE SELF-STERILE VARIETIES. 



No. No. 



Riparia...X 1 Clevener *i Rip 1 Clinton 2 



Rip X 3 Marion 3 Rip X 2 Janesville 1 



Rip X 3 Elvibach 4 Rip X 3 Berckmans 1 



Labrusca.X 4 Aminia 4 Lab X 4 Agawam 2 



Rip X 5 Grein Golden 4 Rip X 5 Mo. Reisling 2 



Lab X 6 Barry 4 Lab X 6 Rogers* No. 32 2 



Lab 7 Wyoming 4 Lab X 7 Lucille 1 



Lab X 8 Black Eagle 4 Lab X 8 Triumph 2 



Lab X 9 Massasoit 4 Lab X 9 Brilliant 2 



Lab X 10 Roscoe 4 Lab X 10 Lindmar 2 



Lin X 11 He.xamer 4 Lin X 11 Bailey i 



*For the significance of these numbers following the names see Bui. 157, .\. Y. E. S. 



Here we have a comparison in each instance of two varieties blooming 

 at the same time or nearly the same time with similar parentage, but one 

 variety being self-sterile and the other self-fertile, the object being to elim- 

 inate so far as possible all differences which might be due to species or strain. 

 This investigation naturally divided itself into two lines ; first, trial of the 

 pollen in sugar solution to see if it would germinate ; second, examination of 

 the pollen under a microscope to see if there were any constant morphological 

 differences between fhat of the self-sterile and self-fertile varieties. In the 

 beginning of this work we were handicapped by a lack of experience in 

 growing grape pollen and a consequent lack of knowledge as to the best 

 solutions in which to grow it, the literature of this subject being not readily 

 accessible. On this account the results from the first four kinds of pollen 

 tested were uncertain. This was due to using a sugar solution which was 

 too weak for this kind of pollen to make a good growth (1 per cent.). The 

 only differences shown in this pollen was in the budding' as none germinated. 

 The Clinton and Janesville both showed buds on from 5 to 10 per cent, of 

 the grains, but the Clevener and Marion showed at the end of four days 

 no change from their condition at time when placed in solution. On June 

 18, 1902, pollen of Elvibach, Berckmans, Aminia and Agawam were placed 

 in hanging drops of 2% per cent, sugar solution. They were examined for 

 three successive days thereafter, and the number of germinations noted. The 

 Elvibach and Aminia pollen did not germinate or even bud. About 4 per 

 cent, kof the Berckmans germinated and about 10 per cent of the Agawam. 

 On the twenty-first pollen was prepared as before except for using a 5 per 

 cent, solution of dextrose in place of the previous medium. The varieties 

 from which pollen was taken in this instance were Grein Golden, Mo. Reisling, 

 Barry, Rogers' No. 32, Wyoming and Lucile. Notes were taken on these 

 cultures on the 23d, at which time they were in the height of their growth, 

 none germinating after that date. At this time the pollen of the Grein Golden 



'The first stage in pollen germination. 



