BY THE SELECTION OF SOMATIC VARIATIONS. 



41 



II. Decrease of Epidekmal Red. 



Bud variations of this sort can be graded as follows: an almost com- 

 plete loss of red on the under surface and about the upper margin, 

 which occurred 2 times, and an apparently complete loss of epidermal 

 red in patterns with spotted or with solid red epidermis, which appeared 

 in 19 instances. A total of 815 plants were grown of patterns having 

 some degree of red in the epidermis. The ratio for complete loss of red 

 was 1 to 8,580 and for all cases of decrease of red it was 1 to 7,760. 



C. CHANGES INVOLVING LEAF-SHAPE. 



The appearance of the laciniate leaf-shape as a fluctuating variation 

 which marked periodicity of development occurred 13 times. (The 

 bud variation giving this type late in 1914 is not included.) The 

 total number of plants grown with entire leaves was 765, hence the ratio 

 on the basis used hitherto was 1 to 11,770. It seems, however, that 

 this basis hardly affords the same degree of accuracy for comparison as 

 it does between the different bud variations in color. Here the change 

 appeared in an entire plant (except one plant grown during winter 

 of 1914-15 and not included in these computations), but as several of 

 these were from a same immediate parent, it may be that the change 

 really arose as a bud variation, with, however, a delayed effect. 



Table 10. — Frequency of changes giving the different types. 



Of the 68 plants grown with the habit of producing laciniate leaves, 

 a single case of persistent change to the entire leaf-shape appeared. 

 There were also 3 cases of clear-cut bud variations involving color 

 changes in these plants. 



SUMMARY AND COMPARISONS. 



For the purpose of comparison, the ratios showing the frequency 

 with which these different types of changes appear are brought together 

 in table 10. In deriving these ratios the total number of plants in which 

 there is possibiHty for the change to occur has been considered. 



These data indicate the tendencies of the bud variations and give a 

 clew to the behavior of the characters in question. In the bud vari- 

 ations, decrease of yellow occurred twice as often as the increase of 

 yellow. Likewise, the loss of red occurred 2.2 times as often as the 



