LUTHER BURBANK 



fertility even when subjected to freezing tempera- 

 ture; being able to live even through snow storms, 

 in contrast to the apricot blossoms which wither 

 under influence of the lightest frost. 



But no elaborate studies have been made to 

 determine whether this difference is associated 

 with anatomical differences of structure, the 

 knowledge of which might guide the plant 

 developer. 



That such differences really exist is suggested 

 by the observed fact that the leaves of very hardy 

 varieties of apples, for example those grown in 

 Siberia, have exceptionally deep layers of epi- 

 dermal cells to give protection to the less hardy 

 cells that make up the bulk of the leaf. Possibly 

 some similar modification of the cells may ac- 

 count for the resistant quality of blossoms that 

 are observed to be able to withstand frost. 

 THE MICROSCOPE MAY HELP 



If such is really the case, the microscopist might 

 come to the aid of the practical fruit grower, 

 pointing out to him the particular trees in his 

 orchard that tend to produce flowers having their 

 structure thus favorably modified. 



This method of selection would have obvious 

 advantages over the method of planting trees at 

 random in the colder regions, and waiting the 

 selective influence of frost. 



[252] 



