134 
DARWINISM 
CHAP. 
cases by downy seeds to be wafted through the air, or by 
hooked or sticky seed-vessels to be carried away, attached to 
skin, wool, or feathers. 
Here, then, we have an enormous extension of the region of 
utility in the vegetable kingdom, and one, moreover, which 
includes almost all the specific characters of plants. For the 
species of plants are usually characterised either by differences 
in the form, size, and colour of the flowers, or of the fruits; 
or, by peculiarities in the shape, size, dentation, or arrange¬ 
ment of the leaves; or by peculiarities in the spines, hairs, or 
down with which various parts of the plant are clothed. In 
the case of plants it must certainly be admitted that “ specific ” 
characters are pre-eminently adaptive ; and though there may 
be some which are not so, yet all those referred to by Darwin 
as having been adduced by various botanists as useless, either 
pertain to genera or higher groups, or are found in some 
plants of a species only—that is, are individual variations not 
specific characters. 
In the case of animals, the most recent wide extension of 
the sphere of utility has been in the matter of their colours 
and markings. It was of course always known that certain 
creatures gained protection by their resemblance to their 
normal surroundings, as in the case of white arctic animals, 
the yellow or brown tints of those living in deserts, and the 
green hues of many birds and insects surrounded by tropical 
vegetation. But of late years these cases have been greatly 
increased both in number and variety, especially in regard to 
those which closely imitate special objects among which they 
live ; and there are other kinds of coloration which long 
appeared to have no use. Large numbers of animals, more 
especially insects, are gaudily coloured, either with vivid hues 
or with striking patterns, so as to be very easily seen. Now 
it has been found, that in almost all these cases the creatures 
possess some special quality which prevents their being 
attacked by the enemies of their kind whenever the 
peculiarity is known; and the brilliant or conspicuous colours 
or markings serve as a warning or signal flag against attack. 
Large numbers of insects thus coloured are nauseous and 
inedible; others, like wasps and bees, have stings; others are 
too hard to be eaten by small birds; while snakes with 
