MISCELLANIES 285 



self-fertile nor self-sterile. Figure 51 shows staminate and per- 

 fect clusters on one vine. Some varieties show no variation 

 in the degree of self-sterility or self-fertility; others behave 

 differently in regard to these characters under different envi- 

 ronment. Now and then the widest variations are to be found 

 in a variety in respect to self-fertility. 



Following the lead of Beach at the New York Agricultural 

 Experiment Station, several workers have made careful studies 



FIG. 51. Staminate and perfect clusters on one vine; right, staminate; 

 left, perfect. 



of the self-fertility of the grape, and now the cultivated varieties 

 of native grapes are divided into four groups in accordance 

 with the degree of self -fertility. Class I includes self-fertile 

 varieties having perfect or nearly perfect clusters; Class II 

 includes self-fertile varieties having clusters loose but market- 

 able ; Class III includes varieties which are so imperfectly self- 

 fertile that the clusters are generally too loose to be marketable ; 

 Class IV includes self-sterile varieties. The following is a list 

 of commonly cultivated grapes classified according to the 

 divisions just given : 



