ISOLATION 187 



flowers have no need to advertise themselves and bid for the 

 favours of insects. Lilac-coloured stamens hang about the spike, 

 beautiful but asking for no reward, like chivalry, the " unbought 

 grace of life." One common wind-fertilised flower, the pink 

 cone of the larch, is certainly conspicuous enough to attract 

 attention and it is difficult to see of what use the colour of these 

 "rosy plumelets" is to the tree. It may be that it is a mere 

 by-product of physiological activities, of the ordinary life pro- 

 cesses going on within the plant. It must be borne in mind that 

 the hues of flowers are due to the accumulation and concentra- 

 tion at certain points of material that the plant possessed in small 

 amount before it put forth blossoms, but which, till that time, 

 was not turned to account. The splendid tints of autumn 

 leaves are due to the processes of life within the trees and as far 

 as we can tell are of no use whatever to the organisms that pro- 

 duce them. Let us to this extent grant that things useless exist 

 in the plant world : there is often material which we count as a 

 by-product since it has not as yet been utilised. To make such 

 a concession is not to give Darwinism away. But were we to 

 own that flowers, with all their colour patterns and their elabor- 

 ate forms, admitted of no Darwinian explanation, then indeed 

 we should have given up so much that it would be well to 

 surrender at discretion. Flowers are no chance by-products nor 

 can any Lamarckian explanation account for them. It is neces- 

 sary to defend Natural Selection stoutly at this point, since 

 attempts have recently been made to show that flowers are 

 inexplicable on Darwinian principles. 



I believe it can be shown that all the colours, shapes, and Flowers 

 scents of flowers are due to insects and their fellow-labourers, and insects 

 such as humming birds. Darwin held this view. And the facts 

 on which he based his theory are these. Nearly all flowering 

 plants require occasional cross-fertilisation : their vigour 

 diminishes if they are not occasionally fertilised with pollen 

 from other flowers of the same species. So vital is this to their 

 continued existence that many of them have become dioecious, 

 i.e., the male and female flowers are on different plants. In the 

 case of others, e.g., the orchids, self-fertilisation is impossible, 



