OLD TYPES AND NEW 



161 



which no color can appear, even though pigment for 

 color may be present, and c is the absence of this 

 factor, while P represents a purple pigment factor 

 which only finds expression in the somatoplasm when 



FIG. 49. Diagram to illustrate the possible progeny from two hetero- 

 zygous purple sweet peas according to data from Bateson. C, color 

 factor (large circles) ; c, absence of C (small circles) ; P, pigment fac- 

 tor (large crosses) ; p, absence of P (small crosses). In the zygotes 

 within the checkerboard squares the gametic symbols are superimposed. 



taken together with the color factor C. The small 

 letter/ p stands for the absence of the purple pigment 

 factor^ "It will be seen that each of the white sweet 

 peas whose formulae are given above lack one of the 

 two essential factors for purple color. When the 





