138 Atavism. 
Plants with pure white flowers such as those belong- 
ing to the variety Alba did not occur in my cultures. I 
have compared the Alba and also the Alba plena directly 
with my plants. Certainly the difference is sometimes 
very slight, especially as the petals of Alba acquire a pale 
lilac color when they fade. They are all gradations 
between the whitest examples and those with the full 
lilac color; the variability in this case is perfectly con- 
tinuous. But between the lilacs and the violets there is 
always a gap; the darkest lilacs seem to be about half as 
dark as the violets ; intermediate stages do not occur. 
The vast majority of the plants have all their petals 
of the same color, but mixed conditions also occur. As 
in other cases there are striped flowers, sectorial and bud- 
variations. Examples of these three groups appeared in 
various years in my cultures but only sparingly. On the 
striped petals the stripes were fine and rare, but they ex- 
hibited the dark violet hue of the original species. The 
instances of sectorial variation have so far been occa- 
sional dark flowers on pale clusters, and on the other 
hand flowers of which one-half of a petal was whitish and 
the other violet (Fig. 24). Bud-/variations occurred on 
plants with very pale flowers, especially when they were 
richly branched and flowered on into the autumn. They 
were always stray twigs on the lower part of the main 
stems ; their flowers were all of the normal violet color. 
But so far I have not been able to obtain seed from them. 
A glance at a large bed reveals the general distribu- 
tion of color. At once the pale flowers are seen to be 
in the majority, whereas the whitish on the one hand 
and the lilac on the other are obviously rarer. The violet 
stand out conspicuously because they are not connected 
with the rest by any gradations. Except for this the varia- 
