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THE AMERICAN NATURALIST [Vol. LI 



in vigorous growing seedlings, gave negative results, agreeing 

 with the results of the two previous years. The experiments thus 

 far conducted show that the species is entirely resistant to arti- 

 ficial inoculations. P. Besseyi, closely related to P. pumila, also 

 shows considerable resistance. 



The two other species of Prunus referred to as being resistant 

 are P. ilicifolia and P. Caroliniana. They are evergreens and 

 are not now considered as strictly belonging to the genus Prunus. 

 They do not readily unite by grafting or budding with varieties 

 of the stone fruits. P. pumila is a shrub and while this stock 

 readily unites with many of the varieties of the stone fruits it 

 probably would dwarf the tree more or less and might sprout. 

 It is, however, readily grown from pits or cuttings. 



TABLE VII 



In each of the inoculation experiments, ten punci 

 made, hence the number of inoculations divided 1 

 the number of separate experiments made with the vari 



In the two tables, VII and VIII, where the inoculations of t 

 years 1913 and 1914 have been summarized, there is a reasonable 

 degree of consistency between the percentages shown for the dif- 

 ferent hosts. Other varieties of P. persica possibly should be 

 further tested, although such varieties as Elberta, Saucer 

 Peento, Salway, Lovell and Muir seedlings have not shown j 

 marked resistance. 



Any of the stock as listed in Tables VII and VIII that « 

 less than 50 per cent, infection are more or less pron 

 the experimental work with artificial inoculations : 



