THE HORTICULTURAL SOCIETY OF NEW YORK 



because of vegetative propagation or because plants are grown 

 either singly or in clonal blocks. 



With these eliminations, we may now make the inquiry : When 

 does the growing of a clonal variety of itself reduce the fruit pro- 

 duction of which the variety is capable? The answers may be 

 stated as follows, embracing three groups of conditions: 



1. When the variety has flowers that are entirely or decidedly 

 pistillate — a grade of intersexes rather frequent in many kinds 

 of plants. 



2. When adaptations prevent or limit both self- and close-pollina- 

 tion. 



3. When self- and close-pollinations do not result in fertilization 

 necessary for fruit setting. 



These may be discussed briefly and in the order given. 



INTERSEXES IN FRUIT CROPS 



The Dates, Figs, Persimmons, Papayas, Strawberries, and 

 Grapes illustrate well the fact that among the numerous individuals 

 of a species or a race there are often different degrees in the rela- 

 tive development of the two sexes in the flowers which affect the 

 ability to self-pollinate. These are deviations from the perfect 

 type of flower with loss of either pistillate or staminate potency, 

 giving frequently numerous grades of intersexes. The abihty 

 to bear fruit is limited to those individuals or clonal varieties that 

 are more or less potent in femaleness and in these there is the 

 possibility of self- or close-pollination only when stamens or 

 staminate flowers are also developed. Otherwise there is need for 

 cross-pollination. In such plants the problems of fruit setting, 

 as far as pollination is concerned, are solved either by hand pollin- 

 ation as in dates, by supplying pollen-bearing flowers together with 

 the insects to carry the pollen as in the Smyrna Fig, by proper 

 interplanting of pistillate with either male or perfect-flowered 

 plants as for certain varieties of Strawberries and for Muscadine 

 Grapes, or in the development of perfect-flowered and self-pollin- 

 ating varieties as was done in the Strawberry and is now being 

 done in the Muscadine Grapes. 



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