304 
DARWINISM 
CHAP. 
Colours of Fmits. 
It is when we come to the essential parts of plants on 
which their perpetuation and distribution depends, that we 
find colour largely utilised for a distinct purpose in flowers 
and fruits. In the former we find attractive colours and 
guiding marks to secure cross - fertilisation by insects; in 
the latter attractive or protective coloration, the first to 
attract birds or other animals when the fruits are intended to be 
eaten, the second to enable them to escape being eaten when 
it would be injurious to the species. The colour phenomena 
of fruits being much the most simple will be considered first. 
The perpetuation and therefore the very existence of each 
species of flowering plant depend upon its seeds being pre¬ 
served from destruction and more or less effectually dispersed 
over a considerable area. The dispersal is effected either 
mechanically or by the agency of animals. Mechanical dis¬ 
persal is chiefly by means of air-currents, and large numbers 
of seeds are specially adapted to be so carried, either by being 
clothed with down or pappus, as in the well-known thistle and 
dandelion seeds; by having wings or other appendages, as in 
the sycamore, birch, and many other trees; by being thrown 
to a considerable distance by the splitting of the seed-vessel, 
and by many other curious devices . 1 A ery large numbers of 
seeds, however, are so small and light that they can be carried 
enormous distances by gales of wind, more especially as most 
of this kind are flattened or curved, so as to expose a large 
surface in proportion to their weight. Those which are 
carried by animals have their surfaces, or that of the seed- 
vessel, armed with minute hooks, or some prickly covering 
which attaches itself to the hair of mammalia or the feathers 
of birds, as in the burdock, cleavers, and many other species. 
Others again are sticky, as in Plumbago europsea, mistletoe, 
and many foreign plants. 
All the seeds or seed-vessels which are adapted to be 
dispersed in any of these ways are of dull protective tints, so 
that when they fall on tin; ground they are almost indis¬ 
tinguishable ; besides which, they are usually small, hard, and 
1 For a popular sketch of these, see Sir J. Lubbock’s Flowers, Fruits, and 
Leaves, or any general botanical work. 
