THE GENOTYPICAL RESPONSE OF THE PLANT 227 
ness of the leaves, the posi- 
tion of the leaves (prostrate 
or ascending), the shape of 
the bracts, etc. 
In order to make clear 
the genotypical constitution 
of the plant as to the form 
of growth, a cross was made 
in 1919 between the nearly 
erect Vellinge plant (fig. 7) 
and the spreading Torekov 
plant (fig. 8). The resulting 
F, was intermediate, none 
of the bastards obtained (12 
in number) being as erect 
as the one parent, and none 
as prostrate as the other. 
Several of the F;-plants 
were crossed with each other Fig. 7. Centaurea jacea. Behaviour of Vellinge 
dwarf in culture. 
(C. jacea is wholly self-ste- 
rile) but the fruits were 
found to be eaten 
by a larva and only 
one of the plants 
was found to have 
some intact fruits 
left. The 30 fruits 
sown gave 26 indivi- 
duals, which were 
already brought to 
flower in 1921. They 
show segregation in- 
to 2 nearly erect, 20 
intermediates and 4 
spreading. Although Fig. 8 Centaurea jacea. Behaviour of Torekov 
this F,-generation is dwarf in culture. 
too small to allow of 
any factorial scheme, the segregation evidently involves several factors; 
it is mentioned here to show the hereditary nature of the characteri- 
stics in question. The cross has been repeated this year. 
Hereditas II. 16 
