LUTHER BURBANK 



increase of the flower, although productivity was 

 also emphasized. 



Indeed, it is to the fact of such stimulus of 

 growth by hybridization that my success in devel- 

 oping the gigantic races of spineless cactus is due. 

 HYBRIDIZING MATERIALS AND METHODS 



The hand pollenizing of the cactus, which was 

 the foundation of these experiments in the pro- 

 ducing of the new spineless races, presents no 

 technical difficulties yet requires to be carried oul 

 in a particular way. 



The cactus flowers open only in the very hottesl 

 part of the day, and within fifteen minutes aftei 

 the pollen-bearers are exposed there is probabilil 

 that the wind or bees will have accomplished self- 

 fertilization of many of the flowers. It is necej 

 sary, therefore, for the experimenter to be on the 

 spot, to anticipate the opening of the flower. 



Our method was to collect pollen in watch cry* 

 tals, and, if necessary, keep it until the flowers w< 

 wished to pollenize were matured. As the diffei 

 ent varieties of cactus bloom at different seasons, 

 it was sometimes necessary to keep the pollen for 

 a considerable period. 



When the plant to be pollenized is ready t< 

 bloom, nothing more is necessary than to remove 

 its stamens just before they are matured, and to 

 dust pollen from watch crystal with a camel's hair 



[184] 



