ON THE QUICK GROWING WALNUT 
be a thousand subordinate factors for form of 
flower; a thousand others for texture of petal; a 
thousand others for odor; yet another thousand for 
hardiness; and so on for each and every patent 
characteristic of flower and twig and stem and root 
of the plant. In the aggregate, let us say, there are 
a thousand different “unit characters,” each made 
up of a thousand minor factors, so that the total 
number of hereditary factors stored in the germ- 
plasm and fighting for recognition, in the case of 
a single plant, is a round million. 
Each of these million factors has been devel- 
oped in the long slow process of evolution, one 
after another added, generation by generation, or 
era by era, beginning with the time when the 
remote primordial progenitor of the plant was a 
single-cell organism. 
In the course of the ages, development has 
taken place along divers lines, and it has come to 
pass that certain combinations of hereditary fact- 
ors have been grouped into systems that have so 
long been working in harmony together that they 
cannot be separated. The members of one such 
group determine the architecture of the root; the 
members of another group determine the archi- 
tecture of the stem; and so on for each of the 
patent characters. 
But there are other groups of factors that are 
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