196 



Rydberg : What is Prunus insititia 



had the reputation of the older Koch and never can claim in the 

 same sense the title, "the acknowledged authority/' Professor 

 Waugh's remark on Karl Koch having changed his opinion has 

 therefore no bearing on my statement. 



When I spoke of the non-existence of P. insititia in America 

 I meant, of course, in the wild state. The existence of a plant in 

 an orchard, garden, greenhouse or in a pot on the window-sill, is 

 to me, as a pure and simple field botanist, the same as non-exist- 

 ence. 





