BUTTERCUP EVOLUTION 



This change has doubtless been brought about 

 owing to adaptation to a different class of 

 insects, which the watery surroundings would 

 account for. The second point is that the plant is 

 entirely free from hairs. 



Now, many of the buttercups possess hairy 

 stems and leaves, because they are troubled by 

 creeping insects, such as ants, which climb their 

 stems and rifle the flowers of their honey without 

 pollinating their stigmas. Nothing baffles such 

 depredating insects so effectually as a thicket of 

 hairs. You have only to examine the turned-back 

 and hairy calyx of the bulbous buttercup as it 

 presses closely against the stem to see how per- 

 fectly it bars the entrance to the flowers from 

 below — no ant can reach their nectar. The water 

 buttercup has no such protection ; surrounded by 

 water, as its stems are, no creeping insects can 

 reach its flowers, only the winged and proper fer- 

 tilising insects can approach its nectar ; hence hairs 

 on its stems or leaves would be superfluous. 



Thus we see that, even amongst the buttercups 

 themselves, each species possesses particular charac- 

 teristics that are of service in its economy ; also, 

 it is obvious how external conditions influence the 

 course of the evolution of the species. The same 

 facts, too, explain how the higher types, such as 

 the Globe-flower {Trollius eiiropmcs), the Green 

 Hellebore {Helleborus viridis), the Christmas 

 Rose (//. niger), the Marsh Marigold {Caltha 

 pahistris), the Anemone {A?ie?no7ie nemorosa), 

 the Traveller's Joy (Clematis vitalda), etc., came 

 M 177 



