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THE AMEBIC AN NATURALIST [Vol. XLVIH 



gosis seems wholly incidental. It follows from the circum- 

 stance that usually only one of the two V factors of so- 

 matic cells is modified. My own data do not in fact show 

 that the change always affects only one of the factors at a 

 time. While the results prove that this is true in a part 

 of the cases at least, the F 1 ratios suggest the possibility 

 of both factors being modified in some cases. 



It is of course utterly impossible at the present time to 

 conceive of the cause or even of the nature of this change 

 in factors from V to 8. We can only conjecture at pres- 

 ent as to whether the change may possibly be associated 

 with changing metabolic processes in the maturing plant, 

 or perhaps be connected in some way with changing ex- 

 ternal influences, or even be a quality inherent in the V 

 factor itself. It is perhaps significant that in maize, at 

 least, the change, whatever its cause, occurs very rarely 

 early in the life of the plant and apparently becomes in- 

 creasingly more frequent as the plant matures. Wholly 

 red ears in variegated-eared plants are extremely rare ; 

 large patches of red grains are somewhat less rare ; indi- 

 vidual red grains occur on most variegated ears; red 

 stripes on the individual grains are very frequent, in fact 

 all but universal in some strains, though in other strains 

 — very light variegated ones — there may be only a few 

 striped grains on a whole ear, the others being wholly 

 colorless. As a matter of fact, even the presence of an 

 ear with red pericarp throughout on a variegated-eared 

 plant may not be good evidence that the change in factors 

 occurred before the ear began to form. If the change 

 took place before the ear was laid down, it would seem 

 that the cob should always be self -red, since the red-eared 

 progeny of such modified grains of the variegated parent 

 plant invariably have red cobs, and cob and pericarp 

 colors are coupled absolutely in later generations. But 

 red ears, or nearly red ears, with light variegated instead 

 of red cobs, have been found to occur as somatic variations 

 on variegated-eared plants. Such behavior suggests that 

 sometimes the factor change may occur almost simul- 



