VI 
DIFFICULTIES AND OBJECTIONS 
133 
and colours of the flowers, the shapes and arrangement of the 
leaves, and the numerous other external characters of the 
whole plant. But since Mr. Darwin showed that plants 
gained both in vigour and in fertility by being crossed with 
other individuals of the same species, and that this crossing 
Avas usually effected by insects which, in search of nectar or 
pollen, carried the pollen from one plant to the flowers of 
another plant, almost every detail is found to have a purpose 
and a use. The shape, the size, and the colour of the petals, 
even the streaks and spots with which they are adorned, the 
position in which they stand, the movements of the stamens 
and pistil at various times, especially at the period of, and 
just after, fertilisation, have been proved to be strictly 
adaptive in so many cases that botanists now believe that all 
the external characters of flowers either are or have been of 
use to the species. 
It has also been shown, by Kerner and other botanists, 
that another set of characteristics have relation to the pre¬ 
vention of ants, slugs, and other animals from reaching the 
flowers, because these creatures would devour or injure 
them without effecting fertilisation. The spines, hairs, 
or sticky glands on the stem or flower-stalk, the curious 
hairs or processes shutting up the flower, or sometimes 
even the extreme smoothness and polish of the outside of 
the petals so that few insects can hang to the part, have 
been shown to be related to the possible intrusion of 
these “unbidden guests.” 1 And, still more recently, attempts 
have been made by Grant Allen and Sir John Lubbock 
to account for the innumerable forms, textures, and groupings 
of leaves, by their relation to the needs of the plants 
themselves; and there can be little doubt that these 
attempts will be ultimately successful. Again, just as flowers 
have been adapted to secure fertilisation or cross-fertilisation, 
fruits have been developed to assist in the dispersal of seeds ; 
and their forms, sizes, juices, and colours can be shown to be 
specially adapted to secure such dispersal by the agency of 
birds and mammals; while the same end is secured in other 
1 See Kerner’s Flowers and their Unhidden Guests for numerous other 
structures and peculiarities of plants which are shown to be adaptive and 
useful. 
