ON THE ALMOND 
on the offspring. The parents were a shade more 
widely removed from each other genetically than 
were, for example, the plum and the apricot or 
the Persian and California walnuts. 
Conceivably this fact, and not the mixed ances- 
try of either parent, may have accounted for the 
diversity of form of the progeny. 
As the plum-almond hybrids were sterile, it is 
obvious that the experiments through which I had 
hoped to develop new varieties and perhaps new 
species of fruits could go no further in this direc- 
tion. It is of course possible that individual plums 
and almonds or different varieties of the two races 
might be found that would combine to produce 
fertile offspring. This supposition finds support 
in the fact that my earliest crosses between the 
plum and the apricot were also sterile; whereas 
later ones produced the fertile plumcot, as the 
reader is aware. . 
So it is obviously worth while to continue the 
experiments of hybridizing the plum and the 
almond, and there is every reason to hope that 
interesting and valuable results may be attained. 
My own experiments, however, although they 
have been repeated occasionally and have never 
been quite lost sight of during the twenty-five years 
that have intervened since the first tests were 
made, have produced only the anomalous results 
[71] 
