1062 
A crossing of two of the varieties which has not yet been discussed 
here, viz. of the common white with the narrow-petalled white, 
shows on the basis of their genotypic composition, that the narrow- 
petalled white flax, although it has much narrower petals than 
the common white, nevertheless possesses the same factors for the 
breadth. 
For in this crossing there arise in F, white flowering individuals 
of the composition AAbbee, in which therefore B as well as C are 
absent and which have the same breadth as the common white 
flax. This proves, that the factors B and C do not regulate the 
breadth of the petals, but that there are present other factors for 
breadth in the two varieties crossed. If these factors for breadth 
were different for the two varieties, then the above mentioned indi- 
viduals would necessarily belong to different types of breadth, 
some narrow like the narrow-petalled flax, others broader like the 
common white or intermediate, possibly even narrower or broader 
than the P-varieties. This is not the case. All individuals of the 
composition AAbdcc are of the same type of breadth. From this it 
follows that the common white and the narrow-petalled white flax 
have the same factors for breadth. Nevertheless the narrow-petalled 
flax is narrower than the common white. There is therefore present 
in these varieties some cause which partially inhibits the factors for 
breadth. This must be the factor C, for as soon as this factor is 
wanting as in the above mentioned individuals in #, of the compo- 
sition AAbbee; the breadth is equal to that of the common white 
flax. This factor C, which together with B, gives the blue colour, 
is therefore seen to be an inhibiting factor for the factors of breadth. 
The factor C also occurs, however, in the common blue flax 
AABBCC, which is nevertheless not narrower than the common 
white flax. The reason for this must be the presence of factor 5 
which prevents the inhibiting action of Con the factors for breadth. This 
agrees with what I have already published *) concerning the action of the 
factors B and C with reference to the crisping of the petal margin, 
the numibers of seeds per fruit and the germinating-power of the seed. 
For the factor C is also the cause of the crisping of the petal apex, of 
the diminution of the number of seeds per fruit and of the diminution of 
the germinating-power of the seed, whilst the factor 5 prevents this 
action of C. Here the same relation for broadness presents itself; 
C causes a diminution of breadth and £ again abolishes the inhi- 
biting action of C. 
It is now necessary to examine whether indeed all the phenomena 
1 Le. Vol. XII, 1915, p. 217. 
