BUTTERCUP EVOLUTION 



suppress their coloured petals merely to promote 

 their sepals into similar coloured organs ? That is 

 a point which, so far as I know, seems uniformly 

 overlooked in explanatory botanical works. 



The explanation can be found, I think, from 

 analogy in comparing these with other members of 

 the famil}^ group. I have before mentioned that 

 the typical or simple buttercup has a little honey 

 gland near the base of each petal. Now, if we 

 turn to the garden hellebore and the globe-flower, 

 we find that these flowers, like the clematis and 

 the anemone, possess a coloured calyx ; but they 

 also have petals besides. However, these petals 

 are dwarfed and serve only as nectaries. That 

 fact is the key to the explanation of the coloured 

 sepals. Originall}^ as seen in the buttercups, the 

 nectaries were insignificant little honey-secreting 

 glands, and the globe-flower and the hellebore in 

 developing their nectaries necessarily had to sacri- 

 fice their petals, for the nectaries were part of the 

 petals. Colour and size were then largely evolved 

 in the sepals to advertise the developing nectaries. 



So far the explanation is simple enough. How 

 came the anemone and the clematis, though, each 

 to possess a conspicuously coloured calyx and yet 

 have no nectaries ? All flowers that do not 

 produce honey are rich in pollen, usually having 

 numerous stamens ; dog-roses and poppies are 

 familiar examples. As we have seen, one of the 

 chief characteristics of the Buttercup family is its 

 numerous stamens. Now there are many pollen- 

 eating and pollen-collecting insects, and these 



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