108 LUTHER BURBANK 



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 

 out in a particular way. 



The cactus flowers open only in the very 

 hottest part of the day, and within fifteen min- 

 utes after the pollen bearers are exposed there 

 is probability that the wind or bees will have 

 accomplished self-fertilization of many of the 

 flowers. It is necessary, therefore, for the 

 experimenter to be on the spot, to anticipate the 

 opening of the flower. 



Our method was to collect pollen in watch 

 crystals, and, if necessary, keep it until 

 the flowers we wished to pollenize were ma- 

 tured. As the different varieties of cactus 

 bloom at different seasons, it was sometimes 

 necessary to keep pollen for a considerable 

 period. 



When the plant to be pollenized is ready to 

 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 brush over the receptive stigma, being care- 

 ful not to allow the brush to become smeared 



