No. 601] RESISTANCE OF PRUNUS TO CROWN GALL 



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Prunus Allegheniensis, P. Americana, P. Amygdalus, P. ander- 

 sonii, P. Armeniaca, P. Armeniaca, var. Mikado, P. Avium, P. 

 Besseyi, P. Caroliniana, P. cerasifera, P. cerasifera, var. divari- 

 cata, P. cerasifera, var. Plant eriensis, P. domcstica, several dif- 

 ferent varieties, P. eriogyna, P. glandulosa, P. hortula^na, P. ilici- 

 folia, P. integrifolia, P. Japonica, P. maritima, P. Mahaleh, P. 

 Mitis, P. monticola, P. Mume, P. munsoniana, P. nigra, P. ortho- 

 sepala, P. Pennsylvanica, P. Persica, several varieties, P. platy- 

 carpa, P. pumila (Linn.), P. serotina, P. Simonii, P. Watsoni. 



All the above hosts gave positive results from artificial inocu- 

 lation, except P. pumila, P. ilicifoUa and P. Caroliniana. These 

 three hosts were inoculated during 1913 and 1914 and have 

 always showed negative results. P. ilicifolia and P. Caroliniana 

 were on their own roots and were not making very rapid growth 

 at the time of the experiment, but it seems almost impossible 

 that they should not have been in a susceptible condition some 

 time during the period from May to September. P. pumila made 

 rapid growth, as it was grafted on peach stock, but never showed 



