1920] 



COULTER— A LEU RONE COLOR 



425 



3. In many cases the exact genotype, with reference to the R 

 and C factors, can be distinguished by superficial appearance. 



4. The particolored grains of East and Hayes were identified. 

 In these some partial substitute enables the P and R factors to 



even in the absence of C. This substitute is 

 effectiveness is limited bv local conditions in 



themselves 



heritable, 



hole 



Mottling (Emerson 



h the male narent c 



? 



comes 



— — * — — 



heritable factor or factors. This factor occurs in the C tester 

 family, and is dominant in crosses with families which do not show 

 mottling. The R tester family seems to contain a different factor, 

 which produces apparent mottling only in a small percentage of the 

 expectations. 



University of Chicago 



i 



