WHAT IS THE EXPLANATION OF THIS CHANGE? 



Instead of a solid red, this sunflower is nearly half yellow. In one case the dividing line 

 between the two colors runs down the middle of a ray. The yellow color is not very clear, 

 but is suffused with red. Generally mutations are supposed to occur only in germ-cells, 

 and strong objections have been made by some writers to assuming that they take place in 

 body-cells. But cases like this sunflower seem to be more easily explained by the latter 

 hypothesis than by any other. (Fig. 11.) 



case was of a different sort. In a 

 sunflower with fine dark red rays were 

 three heads, each lacking altogether 

 about two rays, leaving a space. The 

 outer disc florets were also lacking at 

 the same place. The three heads were 

 on quite different long branches, ex- 

 tending from three different sides of 

 the stem. Here the mutation appar- 

 ently had lethal results. 



My colleague, Dr. Geo. Norlin, who 

 specializes in dahlias, showed me last 

 year a singular variety called cockatoo. 

 The flowers, are lemon yellow, but 

 some heads have the flowers white, 

 faintly pinkish, the rays lemon at base. 

 Dr. Norlin tells me that this production 

 of diverse heads on the same plant is a 

 regular character of this variety. This 

 is suggestive of chemical instability, 



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