LUTHER BURBANK 



to their practical horticultural results, the experi- 

 ments gave some interesting illustrations of heredi- 

 tary influence, 



In particular I observed that when the double 

 marigolds were crossed with the perennial single 

 species above mentioned all the hybrids were 

 single. Moreover, if I am not mistaken, they were 

 all annuals, though the perennial marigold was 

 the mother plant in every case. 



It is interesting to recall that precisely the op- 

 posite result was produced in hybridizing the pop- 

 pies. In that case the union of an annual and a 

 perennial poppy produced hybrids all of which 

 were perennials. 



One of the best marigolds with which I have 

 worked is called the lemonball. It is of the African 

 type, and it produces great lemon-yellow blossoms 

 in abundance, blooming throughout the entire sea- 

 son. The best specimens are thoroughly double, 

 but if the seed is saved from the most double blos- 

 soms, almost half of the seedling will bear single 

 flowers or those not perfectly double. 



It is obvious that the factors for singleness and 

 doubleness tend to be segregated, and that the 

 strains of the double marigold have not all been 

 isolated in such a way as to produce germ plasm 

 that is unmixed as regards the factors for number 

 of petals. 



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