LUTHER BURBANK 



The open secret, of course, is to blend the 

 different strains of heredity by hybridizing the 

 various Opuntias, and to select for propagation 

 the seedlings that reveal the spineless condition 

 in combination with other desired qualities. 

 A SPINELESS RACE ACHIEVED 



From the outset I had been making hybridizing 

 experiments, in which I utilized in particular the 

 hardiest races of Opuntias that I could find, choos- 

 ing, of course, at the same time, those that showed 

 a tendency to produce relatively sparse crops of 

 spines. 



In this way I had developed races of cactus 

 that though small in size were hardy, and thai 

 ultimately, after nine years' work, produced speci- 

 mens that were absolutely free from spines. After 

 the spines were gone, however, there remained 

 spicules, which grow in little clusters of several 

 hundred here and there over the surface of the 

 leaf, and which are an even greater annoyance 

 than the larger spines to the plant experimenter, 

 although they are sometimes ignored by browsing 

 beasts. At the present day absolutely smooth ones 

 have been produced on my grounds, bearing also 

 smooth, handsome fruit of excellent quality. As 

 these have come from a stock hardier than any 

 oak tree, they can probably be grown in Alaska. 



The hardy and partially spineless cactuses first 



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