OD 
The second type, as regards breadth of the petals, occurs in the 
ordinary blue flax, commonly cultivated in the Dutch province of 
Groningen, and in the flax with white flowers, grown in some 
districts of the neighbouring province of Friesland. These two agree 
in the length and also in the breadth of the petals. For plants 
grown under identical conditions, the average breadth of the petals 
from 30 flowers, taken from 30 different individuals, was 7.0 mm. 
for the common blue flax and 7.1 mm. for the common white. The 
small difference between these values may here be neglected. 
The third type of petal-breadth occurs in another variety with 
white flowers. This was formerly described under the names Vilmorin 
white') and erisped white’). The latter name was applied to this 
variety to distinguish it from the common white flax, which like 
the common blue and the Egyptian, has quite flat petals, whereas 
in the crisped white flax the apical margin of the petal is somewhat 
crispy and rolled upwards at the sides. The petals are further 
distinguished from those of the common blue and white flaxes, by 
being much narrower. Since the margin is only erisped at the top 
and the rest of the lamina is flat, the greatest breadth is easily 
determined. In 50 different plants the breadth of a single petal was 
measured: the mean was 3.3 mm., i.e. less than half that of the 
other white and of the common blue flax. The length of the petal, 
however, is about the same on all three varieties. Thus for 50 petals 
the average was 10.1 mm., as against an average length of 10.6 mm. 
for the common white, and 10.3 mm. for the common blue flax. 
The Egyptian flax has much longer petals, their average length 
being 16.2 mm. 
As is evident from the average values for the petal-breadth viz. 
13.4, 7.1, 7.0 and 3.3 mm., the above mentioned varieties differ 
considerably in this character; two of the four belong to the same 
type as regards breadth, ie. that of 7 mm., but these two differ 
in colour. This paper deals with the behaviour of the petal-breadth 
and the correlation between breadth and colour in the various 
crosses between the four varieties. For details regarding the behaviour 
of the colour of the flowers I refer to the above quoted paper of 
1915. Here it is enough to know that on crossing a white with a 
blue variety, blue and white individuals occur in #,. The ratios of 
these do not concern us here. First the successive crosses with 
1) The explanation of an apparent exception to MENDEL’s law of segregation. 
Proc. Kon. Akad, v. Wetensch. Amsterdam Vol. XVI, 1914, p. 1021. 
*) Die genotypische Zusammensetzung einiger Varietäten derselben Art und ihr 
genetischer Zusammenhang. Rec. d. Tray. bot. Néerl. Vol. XII, 1915, p. 219. 
