Effect of Cultivation 245 
others, de Vries’ tried to show that garden-races have been produced 
only from spontaneous types which occur in a wild state or from 
sub-races, which the breeder has accidentally discovered but not 
originated. In a small number of cases only has de Vries adduced 
definite proof. On the other side we have the work of Korschinsky? 
which shows that whole series of garden-races have made their 
appearance only after years of cultivation. In the majority of races 
we are entirely ignorant of their origin. 
It is, however, a fact that if a plant is removed from natural 
conditions into cultivation, a well-marked variation occurs. The 
well-known plant-breeder, L. de Vilmorin’, speaking from his own 
experience, states that a plant is induced to “affoler,” that is to 
exhibit all possible variations from which the breeder may make a 
further selection only after cultivation for several generations. The 
effect of cultivation was particularly striking in Veronica chamaedrys* 
which, in spite of its wide distribution in nature, varies very little. 
After a few years of cultivation this “good” and constant species 
becomes highly variable. The specimens on which the experiments 
were made were three modified inflorescence cuttings, the parent- 
plants of which certainly exhibited no striking abnormalities. In a 
short time many hitherto latent potentialities became apparent, so 
that characters, never previously observed, or at least very rarely, 
were exhibited, such as scattered leaf-arrangement, torsion, terminal 
or branched inflorescences, the conversion of the inflorescence into 
foliage-shoots, every conceivable alteration in the colour of fiowers, 
the assumption of a green colour by parts of the flowers, the 
proliferation of flowers. 
All this points to some disturbance in the species resulting from 
methods of cultivation. It has, however, not yet been possible to pro- 
duce constant races with any one of these modified characters. But 
variations appeared among the seedlings, some of which, e.g. yellow 
variegation, were not inheritable, while others have proved constant. 
This holds good, so far as we know at present, for a small rose-coloured 
form which is to be reckoned as a mutation. Thus the prospect of 
producing new races by cultivation appears to be full of promise. 
So long as the view is held that good nourishment, i.e. a plentiful 
supply of water and salts, constitutes the essential characteristic of 
garden-cultivation, we can hardly conceive that new mutations can 
be thus produced. But perhaps the view here put forward in regard 
to the production of form throws new light on this puzzling problem. 
1 Mutationstheorie, Vol. 1. pp. 412 et seq. 
° Korschinsky, ‘“‘ Heterogenesis und Evolution,” Flora, 1901. 
3 L, de Vilmorin, Notices sur Vamélioration des plantes, Paris, 1886, p. 36. 
4 Klebs, Kiinstliche Metamorphosen, Stuttgart, 1906, p. 152. 
