LUTHER BURBANK 
nut has not as yet been made to bear in childhood, 
so to speak, as the chestnuts and some strains of 
the English walnut now do. But in this regard 
also there would doubiless be rapid improvement 
under selection. 
The actual method of hand-pollenizing is very 
simple. Nothing more is necessary than to break 
off the flower bearing branch, just at the right 
time, and shake it over the flowers of the pistillate 
parent. 
Of course one cannot make sure that some of 
the flowers will not be self-fertilized, but by plant- 
ing a large number of the nuts, it will be possible 
to determine from the appearance of the seedlings 
which ones are hybrids. Also where the trees 
grow close together, there are sometimes natural 
hybrids, though I was not aware of this when I 
made my first experiments, in years 1875-1880. 
When I made my first experiments at hybrid- 
izing the walnuts, I planted the seeds of the entire 
tree. In the rows of seedlings, I could at once 
determine which ones were hybridized, as these 
grew far more rapidly than the others, besides dif- 
fering notably in general appearance. 
My first experiment was made with two black 
walnuts, and it was the success of this that led me 
to attempt to hybridize the Persian and California 
walnuts the following year. The hybridization in 
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