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THE AMERICAN NATURALIST [Vol. XL VIII 



S—, for they yielded F 2 progenies consisting of reds and 

 whites only. Four of the 11 were obviously SV, for they 

 yielded F 2 's of reds and variegates only. Of the latter 

 F 2 reds, one bred true in F 3 and four again segregated 

 into reds and variegates. 



From a self-red seed of a homozygous, variegated ear 

 that had been cross-pollinated by a pure red race, an F 1 

 red-eared plant was produced and this plant bred true red 

 in F 2 . From a nearly self-red seed of the same varie- 

 gated, parent ear, an F 1 red was produced but yielded 

 reds and variegates in F 2 just as did a similar F x ear 

 from a seed with narrow red stripes (see page 100). The 

 variegated parent ear was VV and the red and near-red 

 grains probably VS. The gametes associated with these 

 grains were V and S. The male gametes were all S. 

 Therefore the F 2 reds were in part VS and in part SS. 



By way of summary, it is recalled that, in all, 28 F, 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 pure 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 x red- 

 eared plants behaved as did the F 1 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 x 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- 



