STUDIES ON THE GENETICS OF FLOWER-COLOURS, ETC. 
125 
perhaps belong to this category, though the behaviour of the i^-orange in F i 
was not yet examined ; so will be perhaps also No. 13, where however no seed 
of white came to germination. —The production of some reds from homozygous 
oranges, as seen in Nos. 1, 2 (F z ), 10, and 25 is also explainable by assuming 
the reversion of one allelomorph, viz. the formation of some gametes CBb 
besides normal Crb, and the occurrence of the fertilisation CBb x Crb or 
CBb x CBb (or their reciprocal), giving rise to red zygotes of the composi¬ 
tion CCBrbb or CCBBbb. —The production of magentas from whites, as 
seen in Nos. 21 and 22 might also be due to the reversional change of one 
single allelomorph ; since the 14-whites in these two Nos. are derived from 
the cross white-II X magenta, and consequently should possess the genotypic 
composition ccBBBB its normal gametes are cBB, and thus the forma¬ 
tion of few gametes CBB by means of the reversion of c into C, and the 
mating of the latter, either with normal gametes cBB or the mutated CBB 
themselves will give rise to magenta zygotes, hetero- in the first and homozygous 
in the second case.—In No. 2 (F) we see the production of magenta from 
red, and tliis is also evidently a simple process consisting in the reversion of 
one b into B, the development of few gametes CBB as the consequence, 
and the fertilisation CBB x CBb or its reciprocal. 
In the production of magentas from oranges, as seen in Nos. 1 and 9, as 
well as that of reds from whites, as seen in No. 4, the occurrence of a 
simultaneous reversion of two allelomorphs should be necessarily assumed. 
Thus in the first of two cases just cited the orange of the composition CCrrbb 
must produce the gametes Crb (normal) and CBB (mutated), and in the 
second the white ccrrbb, the gametes cvb (normal) and CBb (mutated) 1 
The reversion process in No. 27 may be explained as follows :—the 
orange parent is here heterozygous, i.e. of the composition Ccrrbb ; since 
normally the gametes Crb and crb (either male or female) are produced in 
equal numbers their meeting will give rise to 3 oranges : 1 white, so that if 
magentas and reds segregated out in this case are considered to be oranges 
1 The formation of the gametes of two kinds, viz. C lib and CvJB in the first case, and 
that of Cvb and cRb in the second will lead to the same results, but then the fertilisation 
between the two mutated gametes, viz. Cllb x C'vli as well as Cvb x clib (or their reciprocal) 
mi;st be assumed to have occurded. 
