The Oriyin of Striped Flowers. 115 
On the other hand a certain percentage (often 6% and 
more) of the plants raised from the seeds of striped 
flowers and especially of sectorial branches are usually 
uniform blues. 1 
The phenomena of segregation which we have been 
describing are quite common in striped flowers, and any 
one can observe them in Dahlia varidbilis striata (Vol. 
I, Fig. 14, p. 54), Mirabilis Jala pa, Verbena and many 
other favorite garden flowers. Sectorially colored flow- 
ers appear to manifest a tendency towards a simple pro- 
portion between the two parts. Frequently exactly half 
of the flower is atavistic, sometimes a quarter or three 
quarters. I observed the proportion % in white and red 
striped tulips and in partially dark blue and partially pale 
blue flowers of Iris xiphioides, etc. In these cases the 
various types frequently occur on the same plant, or in 
the case of plants grown from bulbs, on examples raised 
through vegetative propagation from a single original 
bulb; for instance on the tulips and Iris just mentioned 
there were also flowers of which one-half of each was 
atavistic. 
Sectorial variability often occurred in my cultures, 
as for instance in the flowerheads of Helichr\suin brac- 
teatiun and the flowers of Papaver nudicaide (Fig. 20), 
in both of which cases stripes or sectors of the color 
belonging to the parent species were superimposed on 
the paler background of the variety. A common balsam 
(Impatiens Balsam ina') whose flowers were usually white 
with fine red stripes bore a branch with red flowers only 
in my garden. The whole breadth of the fasciated stem 
1 A point of great interest to investigate would be the relation 
between sectorial variability and cell division in the vegetation cone ; 
clues which might lead to the solution of many important questions 
would probably be afforded by such an inquiry. 
