MORE MARRIAGE CUSTOMS. 



By the time he reaches another plant they have 



assumed such a position that they are brought 



into contact with the stigma as he sucks the 



honey. But the stigma is gummy too, and makes 



the pollen adhere to it, and in this way cross- 



fertilisation is rendered almost 



a dead certainty. The result 



of these various clever dodges 



is that the orchids have become 



one of the dominant plant- 



families of the world, and in 



the tropics usurp many of the 



best and most favoured posi- 



tions (Fig. 24). 



Darwin has written a most 

 romantic book on the numer- 

 ous devices by which orchids 

 alone attract insects to fertil- 

 ise them. I will say no more 

 of this family, therefore the 

 highest and strangest among 

 the threefold flowers save merely to advise those 

 who wish to know more of this curious sub- 

 ject to look it up in his charming volume. In- 

 stead of pursuing the matter at issue further, I 

 will give one final example in an opposite direc- 

 tion. 



An opposite direction, I say, because all the 

 threefold flowers we have hitherto been consider- 

 ing are examples of a strict upward movement of 

 evolution. Each group we have examined has 

 been higher and more complex than the group 

 before it. But I will now show you an instance, 

 if not of degeneracy, at least of extreme simplifi- 

 cation, which yet produces in the end the best 

 possible results. This instance is that of the 



much enlarged. 



