FLOWER AND SEED COLOUR IN LUPINUS 351 
Cross 9 shows that the meeting of the factors B and V is necessary 
if deep blue colour shall result. Bluish red has been crossed here 
with violet, and F, is blue. The one type alone can not have carried 
the determiners of the blue colour as this colour is dominant 
over bluish red as well as over violet; these must have been distributed 
in the both parent types. The assumption of quite other factors than 
those for bluish red and violet bringing about the synthesis would also 
explain the matter, and the mere occurrence of a blue coloured F}- 
generation in this cross is no adequate proof. The segregation in F, 
and F, would then have been another, however. Bluish red and 
violet individuals are found in the same number in F;, and violets 
never originate from bluish reds in F:, or vice versa. Plants of these 
colours never carry more than one of the determiners in question; the 
flower is always blue in the plants carrying both determiners. Thus 
this colour does not depend on a specific factor; it is on the contrary 
a compound character genetically, and the factors involved are the 
ones denoted for bluish red and violet. | 
The effect of these factors, on the other hand, depends on the 
factor for pure red or R. The B-factor induces a faint blue colora- 
tion in the red flower, as well as in the brownish red vegetative parts 
of the pure red type. It is apparently a bluing factor. It is another 
example of a factor with bluing effect in red flowers so commonly 
found in widely different genera. An examination of the bluish red 
flowers seems to show, however, that the red pigment has been trans- 
formed into blue pigment only in a limited number of cells. The 
red ground colour remains unchanged to a great extent, and only 
certain parts are more or less covered with a blue tinge. The bluish 
red colour, then, is not a specific colour but a combination of blue 
and red. It seems questionable only for this reason if it is to be com- 
pared with the purple colour in Lathyrus, for instance, a parallel 
which lies close at hand. The blue coloration spreads more diffusely 
in the flower with age, and the similarity with purple colour becomes 
greater. That the B-factor is a bluing factor is clearly seen in its re- 
lation to the seed colour. It has been assumed that the purpose of 
the B-factor with regard to seed colour is to transfer the rust-brown 
pigment of the pure red type into earth-brown. The examination of 
immature seeds shows, however, that the effect in fact also here is 
a blue coloration. Seeds still enclosed in the yellow but not yet 
dry pods show a red-violet coloration of the coloured parts in the 
rust-brown type, while the same parts in the earth-brown type are 
Hereditas II. 22 
