Ernest Warren 
109 
In the gametic group DD x DD (homozygous purple x homozygous pui'ple) 
there were 1620 offspring. These should have been all purple, but there were two 
white plants which occurred in two deeply coloured families and three white 
plants which occurred in one pale-coloured family. I do not believe that there 
was contamination, and it is probable that the two former plants were sports, 
while the three latter plants were produced by selection. 
In the group RR x RR (white x white) there were 336 offspring, and these 
should have been all white, but there were six pale-coloured plants. The difficulty 
in distinguishing a tinged " white " plant from a pale-coloured plant may account 
for this result, but I favour the view that we are here witnessing the beginning of 
a coloured race. 
The result given by DR x DR (heterozygous purple x heterozygous purple) is 
very closely Mendelian. Out of 785 offspring there were 190 white plants while 
the expectation was 196. 
Heterozygous plants crossed with dominants {DR x DD) gave nothing but 
coloured plants, and this was also the case with dominants crossed with recessives 
{DD X RR). 
The gametic groiip DR x RR (heterozygous plants x recessives) gave a result 
which diverged rather widely from the expectation : there were insufficient whites, 
there being 24 whites and .52 purples instead of 38 of each. The numbers are 
somewhat small for drawing conclusions, but it is important to notice that in the 
character of pelorism it was the same gametic group which diverged the most 
widely of all the classes from the theoretical expectation. On the chromosome 
hypothesis it may be conjectured that possibly preferential pairing of the male 
and female chromosomes may explain the discrepancy. 
The Inheritance of the Intensity of Coloration. 
On crossing a purple homozygous plant with a white plant the offspring were 
all hetei'ozygous and all coloured, but the intensity of the coloration was mostly 
reduced very considerably. On selling these offspring the next generation yielded 
some homozygous dominants in which the original colour-intensity of the grand- 
parent was regained ; thus, at first sight it appeared that there had been no real 
dilation of the colour by crossing with the white. This was my Hrst impression 
from the earlier results, but with more extended experience I found that there 
was certain evidence that the crossing with the white did have some deleterious 
action on the intensity of the coloration of the dominant grandchildren, although 
the coloration which appeared was much greater than a half and half blend with 
white. 
If two homozygous dominants of marked difference in colour-intensity were 
crossed, the offspring tended to be intermediate. On selling these offspring the 
next generation was similarly intermediate, and there was no segregation into the 
two different intensities of the grandparents. Thus a true blend of the two 
intensities had taken place. 
