32 
Research Bulletin No. 4 
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, witli 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- 
taneously in the rudiments of every grain so that the 
grains become self -red while the cob remains variegated. 
We might, of course, account for the appearance of self- 
colored grains on a variegated cob on the basis of sepa- 
