Darwin's Artificial and Natural Selection 135 
it is not really necessary to suppose that this would often 
occur, for the same result could be reached by several stages, 
even if the discontinuous variations had been small, and had 
appeared in many individuals simultaneously. After showing 
that in a number of flowers, especially of the Composite and 
Umbelliferze, the individual flowers in the closely crowded 
heads are sometimes formed on a different type, Darwin con- 
cludes: ‘In these several cases, with the exception of that of 
the well-developed ray-florets, which are of service in making 
the flowers conspicuous to insects, natural selection cannot, 
as far as we can judge, have come into play, or only in a 
quite subordinate manner. All these modifications follow 
from the relative position and interaction of the parts; and 
it can hardly be doubted that if all the flowers and leaves on 
the same plant had been subjected to the same external and 
internal condition, as are the flowers and leaves in certain 
positions, all would have been modified in the same manner.” 
Further on we meet with the following remarkable state- 
ment: “But when, from the nature of the organism and of 
the conditions, modifications have been induced which are 
unimportant for the welfare of the species, they may be, and 
apparently often have been, transmitted in nearly the same 
state to numerous, otherwise modified, descendants. It can- 
not have been of much importance to the greater number of 
mammals, birds, or reptiles, whether they were clothed with 
hair, feathers, or scales; yet hair has been transmitted to 
almost all mammals, feathers to all birds, and scales to all 
true reptiles. A structure, whatever it may be, which is 
common to many allied forms, is ranked by us as of high 
systematic importance, and consequently is often assumed to 
be of high vital importance to the species. Thus, as I am 
inclined to believe, morphological differences, which we con- 
sider as important, — such as the arrangement of the leaves, 
the divisions of the flower or of the ovarium, the position of 
the ovules, etc., — first appeared in many cases as fluctuating 
