28 
Research Bulletin No. 4 
By way of summary, it is recalled that, in all, 28 F 1 red- 
eared plants were tested by F 2 progenies. Only one of 
these bred true and that one came from a red grain of an 
ear that had been cross-pollinated by a pnre red race. 
Disregarding the three F 2 red-eared plants thus produced 
and the 9 red ears produced from seeds of variegated ears 
that had been cross-pollinated by white races and that 
therefore could not have bred true, there remain 16 F x 
reds, none of which bred true in F 2 . Had these F 1 red- 
eared plants behaved as did the F x green-leaved plants 
produced by green branches of variegated-leaved parents 
in Correns 's experiments, approximately 5 of the 16 
should have bred true. It will be recalled that Correns 
found that such green branches always produced green- 
leaved and variegated-leaved plants in the ratio of 3:1, 
and that one of the three bred true and the other two 
again segregated, just as must have happened if the green 
branch had been a part of an F 1 hybrid of green with 
variegated instead of a part of a homozygous variegated 
plant. 
The difference between Zea and Mirabilis is, however, 
not a fundamental one, but is due merely to the circum- 
stance that Mirabilis has perfect flowers while Zea is 
monecious. In Mirabilis both male and female gametes 
of a green branch arise from somatic cells in which the V 
factor has changed to a G factor. If a change in only one 
V factor is responsible for the production of the green 
branch, the somatic cells of such a branch must all be VG 
and the results reported by Correns are the only ones to 
be expected. With Zea mays, however, all the grains of 
one ear of a variegated-eared plant might arise from cells 
having VS, so that half of the female gametes would carry 
S, while little or no corresponding change might take 
place in the staminate inflorescence and therefore no (or 
very few) male gametes would carry S. From such an 
ear of maize only about one half, instead of three fourths, 
