32 Bulletin 392 



Fi progeny comprise both flaked whites and flaked solids, indicating 

 a heterozygous condition of the determiners in one of the parents. The 

 Fi flaked sohds when selfed can throw all four types — flaked and unflaked 

 solids, and flaked and unflaked whites. 



If the explanation of this is based on the enzyme theory, which regards 

 such anthocyanic colors as those here dealt with as being the product 

 of interaction between an oxidase and a chromogen, it is seen that the 

 presence of both the chromogen and the oxidase is necessary in order 

 that any color whatever may be visible in the flower. The oxidase may 

 be symbolized by and the chromogen by C. The flaking, then, can 

 be explained by supposing the presence of a locally distributed oxidase F, 

 which reacts with the chromogen C in the same way as does O except 

 that the area of its influence is restricted, which results in the so-called 

 flakes. This chromogen is usually present in the colorless tissues of white 

 flowers (Kraemer, 1906, andWheldale, 1909 b:53). Moreover, the oxidase 

 itself is composed of at least two substances, the peroxide and the per- 

 oxidase (as explained on pages 9 to 11), and unless the peroxide is 

 present along with the chromogen and the peroxidase there will be no 

 production of anthocyanic pigment. But for the sake of simplicity 

 in the present discussion the oxidase is considered as a single "unit- 

 character" where homozygous, and will be symbolized by O. 



In tables 9 to 1 7 are given the data in support of this hypothesis, classified 

 and arranged to show the genetical behavior of the flake character and the 

 segregation of the various types, together with hypothetical formulas 

 explanatory of this behavior. The various types may be symbolized as 

 follows : 



C= Chromogen (almost [?] always present) 

 = Oxidase that reacts with C to give solid color 



F = Oxidase that is locally distributed and acts with C to give colored 

 flakes 



Possible formulas for the various phenotypes as used in the following 

 tables are as follows: 



Plain white = CCooff (la) 



OOFF (lb) 



OOFf (i c) 



OOff (i d) 



OoFF (le) 



cc ^ OoFf (i f) 



Ooff (i g) 



ooFF (i h) 



ooFf (i i) 



ooff (i j) 



Ccooff (ik) 



CcOolf (il) 



148 



