The "poor" bunch of grapes shown here was due to scanty cross-polHna- 

 tion. The variety, known as Brighton, has flowers that produce no viable 

 pollen. Hence setting of fruit on any vine of the clonal variety 



depends o n cross- 



pollination. When 

 this is inadequate 

 there are many miss- 

 i n g berries, small 

 berries or none a t 

 all. Here the few 

 large berries were 

 from flowers that 

 happened to be well 

 cross-pollinated. 



In grapes, the 

 flowers indicate the 

 pollinating ability of 

 the plant or the 

 clonal variety. Those 

 with the male type 

 (/, below) are not 

 able to bear fruit ; 

 they can supply pol- 

 len : those with the 

 perfect flower {2) 

 are self-pollinating 

 and s e 1 f-fruitful : 

 those with the im- 

 perfect type o f 

 flower (?) are self- 

 fruitless and should 

 be interplanted with 

 perfect-flowered va- 

 rieties that bloom at 

 the same time. Then 

 i f insects perform 

 the c r o s s-pollina- 

 tion adequately 

 there will be a set 

 of full bunches. 



