Variation and Heredity 207 
pollen from other species. Here also appeared some of the 
new species, already mentioned, namely, albida, nannella, 
lata, oblongata, rubrinervis, and also two new species, elliptica 
and subovata. 
De Vries also watched the field from which the original 
forms were obtained, and found there many of the new 
species that appeared under cultivation. These were found, 
however, only as weak young plants that rarely flowered. 
Five of the new forms were seen either in the Hilversam 
field, or else raised from seeds that had been collected there. 
These facts show that the new species are not due to cultiva- 
tion, and that they arise year after year from the seeds of 
the parent form, O. /amarckiana. 
CONCLUSIONS 
From the evidence given in the preceding pages it ap- 
pears that the line between fluctuating variations and muta- 
tions may be sharply drawn. If we assume that mutations 
have furnished the material for the process of evolution, the 
whole problem appears in a different light from that in which 
it was placed by Darwin when he assumed that the fluctuating 
variations are the kind which give the material for evolution. 
From the point of view of the mutation theory, species are 
no longer looked upon as having been slowly built up through 
the selection of individual variations, but the elementary 
species, at least, appear at a single advance, and fully formed. 
This need not necessarily mean that great changes have sud- 
denly taken place, and in this respect the mutation theory is 
in accord with Darwin’s view that extreme forms that rarely 
appear, “sports,” have not furnished the material for the 
process of evolution. 
As De Vries has pointed out, each mutation may be different 
from the parent form in only a slight degree for each pojnt, 
although all the points may be different. The most unique 
