VAUIOUS MAllRIAGE CUSTOMS. 101 



gradations. The little winter aconite of our 

 gardens has this peculiarity : the petal and 

 nectary have grown into a sort of tubular honey- 

 cup, much more attractive to greedy insects than 

 the simple scale-bearing petal of the buttercups. 

 But as this involves loss of expanded colour- 

 surface, the winter aconite has made up for 

 the deficiency by colouring its calyx a brilliant 

 yellow, so as to resemble a corolla. Several 

 other buttercup-like plants have even lost their 

 petals altogether, and make coloured sepals do 

 duty in their place. The marsh-marigold, for 

 instance, is one of these ; what look like petals 

 in it are really very brilliant yellow sepals. 

 Moreover, as the marsh-marigold is such a large 

 and handsome flower, it easily attracts insects 

 in early spring ; and this has enabled it to effect 

 an economy in the matter of its carpels or female 

 organs. In the buttercups, we saw, these were 

 very numerous, and each contained only one 

 seed ; in the marsh-marigold, on the other hand, 

 they are reduced to five or ten, but each contains 

 a large number of seeds. This arrangement 

 enables a few acts of fertilisation to sulfice for 

 the whole flower. You will therefore find as 

 a rule that advanced types of flowers have very 

 few carpels — sometimes only one — and that 

 when they are more numerous they are often 

 combined into a single ovary, with one sensitive 

 surface, so that one fertilisation is enough for 

 the whole of them. 



Three familiar -but highly-advanced members 

 of the buttercup group will serve to show the 

 immense changes effected in this respect by 



