200 THE EVOLUTIONIST AT LARGE. 



The outer face of the bindweed, the 

 terior of the cup, so to speak, is prettily 

 marked with five dark russet-red bands, 

 between which the remainder of the corolla 

 is a pale pinky-white in hue. Nothing could 

 be simpler and prettier than this alternation 

 of dark and light belts ; but how is it pro- 

 duced ? Merely thus. The convolvulus 

 blossom in the bud is twisted or contorted 

 round and round, part of the cup being 

 folded inside, while the five joints of the 

 corolla are folded outside, much after the 

 fashion of an umbrella when rolled up. And 

 just as the bits of the umbrella which are 

 exposed when it is folded become faded in 

 colour, so the bits of the bindweed blossom 

 which are outermost in the bud become 

 more deeply oxidised than the other parts, 

 and acquire a russet-red hue. The belted 

 appearance which thus results is really as 

 accidental, if I may use that unphilosophical 

 expression, as the belted appearance of the 

 old umbrella, or the wrinkles caused by the 



