THEORY AND PRACTICE 



the individual flower varies in color, changing 

 from one shade to another in the course of twenty- 

 four hours. 



In the morning on first opening the flowers are 

 pure white, by noon they are a bright pink, and 

 toward evening they have changed to a deep crim- 

 son. All the flowers at present under considera- 

 tion furnish illustrations of dominance of one 

 color factor over another, and on occasion of the 

 blending of factors to produce new colors; but 

 this case in which first one color and then another 

 is dominant in the same flower is altogether out 

 of the ordinary. 



ACCENTUATING DESIRED CHARACTERS 



It remains to be said that the distribution of 

 the various qualities of the plant into opposing 

 couples showing dominance and recessiveness is 

 by no means so clean-cut and explicit in every 

 case as the instances just cited might lead one to 

 expect. In point of fact, it appears to be true that 

 it is only the qualities that are of comparatively 

 recent origin in the evolutionary sense that clearly 

 Mendelize. Such qualities, for example, as the 

 precise length of stem, color of flower, and color of 

 seed pod are far less fundamental than the es- 

 sential qualities of form and anatomical structure 

 of stem and leaf, and the shape and arrangement 

 of the petals and the essential organs of the 

 flower. When these fundamentals are in ques- 

 tion, the hybrid progeny usually show a blending 



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