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 wdiitest 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 flow^ers, sectorial and Imd- 

 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 wdiitish 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- 



