146 LUTHER BURBANK 



Hudson's Bay, in regions where it is not uncom- 

 mon for the mercury to fall sixty degrees below 

 zero. 



The California holly-leaf cherry ( Cerasus iUci- 

 folia) and the Catalina cherry are species that 

 may be available for the development of other 

 desirable varieties for it is not in hardiness alone 

 that the best varieties sometimes are found want- 

 ing; though the species just named are so far 

 separated biologically and physiologically that it 

 will no doubt be impossible to combine them with 

 our more common cherries. 



Many cultivated cherries, for example, are un- 

 able to withstand the warm spring rains without 

 serious loss from cracking of the fruit. Some- 

 times almost an entire crop will thus be ruined. 

 Again many cherries are susceptible to blight. A 

 bulletin issued by the State Commission of Hor- 

 ticulture of California lists more than twenty in- 

 sects leaf hoppers, scales, mites, caterpillars, 

 and borers that prey more or less upon root or 

 bark or leaf of the cherry tree, or that attack its 

 fruit. 



Then there are inherent maladies, such as the 

 tendency to overflow and condensation of sap, 

 forming an injurious gum that may induce decay 

 of bark and wood (called gummosis), to which 

 the cherry is peculiarly liable. 



