BY THE SELECTION OF SOMATIC VARIATIONS. 



35 



made for plants. During the summer of 1914 the G plants remained 

 constant for loss of epidermal red, but bore some leaves with yellow 

 spots. There was, however, a rather weak development of yellow and 

 from a short distance the plants appeared to be pure green. The 

 fluctuations in the development of green and yellow are quite like 

 those in other patterns. The pattern is of special interest in regard 

 to the development of red pigmentation in the subepidermal tissues, 

 especially in the vascular elements giving a reticulated effect well 

 shown in figure 13, and also seen in figure 14a. This condition 

 also prevails in the red blotched types, but is more or less obscured 

 by the more conspicuous epidermal coloration. 



During the summer of 1914 there was no noticeable variation in 

 the amount of red in subepidermal tissues. Cuttings made in the 

 autumn of that year for a new generation exhibited during the winter 

 marked variations in this respect. The summaries given in this paper 

 do not include the generation to which these plants belong, but the 

 behavior of this particular set of plants can be included here. Figure 



Table 9. — Summary of plants with non red epidermis. 



Pattern. 



Green-yellow 



Green and green-yellow spotted . 

 Yellow-green 



Total 

 plants. 



7 

 7 

 4 



Constant 

 for non red 

 epidermis. 



7 

 7 

 4 



Plants 

 giving bud 

 variations. 





 

 



13d gives a leaf painted on February 2, 1915, showing the development 

 of red in the internal tissues. Free-hand sections of such leaves indi- 

 cated that the epidermal cells are non-red. The coloration appears 

 dull, as if glazed over rather than velvety as in the epidermal colora- 

 tion, a contrast due largely to the coloration of the trichomes of 

 the epidermis and which the reproductions do not adequately show. 



Plants with 'pattern yellow-green. — This pattern (fig. 14) identical with 

 that of type yellow-green-red blotched except for the loss of epidermal 

 red, appeared as a sectorial bud variation late in the summer of 1913. 

 The sporting branch was used as a cutting, from which a large plant 

 grew during the winter of 1913 and the following summer. In the 

 winter there was an increase of green, but throughout its growth the 

 part with pattern yellow-green remained constant in respect to the loss 

 of epidermal red. 



Three plants of a new generation were grown during the summer of 

 1914, and these remained constant and uniform for the loss of epidermal 

 red. In regard to the relative positions of green and yellow, the plants 

 were quite constant, but there was a strong tendency for green to 

 increase in winter and decrease in summer, giving such differences as 

 are shown in figures 14 and 14a. 



