"Blossom Hosts aiui Insect Guests 



what has, without doubt, actually been the case, 

 that the early ancestors of a certain flower were 

 self-fertilized. At length, among other continual 

 variations,* certain seedlings showed the singular 

 variation of ripening their pollen in advance of their 

 stigmas or in other ways developed peculiarities 

 which prevented self-fertilization. At the same 

 time that they began to develop this condition, the 

 flowers began to secrete nectar in their cups. A 

 passing insect, lured by the sweets, entered a blos- 

 som, and while sipping its honey dew became dusted 

 with its pollen, which he deposited on the stigma 

 of the next flower he visited, f 



The flower thus fertilized acquired a strain of 

 fresh vigor. Its seedlings coming now into com- 

 petition with the existing weaker self-fertilized 

 forms, by the increased vigor won in the struggle 

 of their immediate surroundings, and inheriting the 

 peculiarity of their parents, showed flowers possess- 

 ing the same cross-fertilizing device. The seeds 

 from these again scattering continued the unequal 

 struggle in a larger and larger field, and in increasing 



* It is this tendency to variation in individual flowers tliat makes 

 it possible for nature to select and preserve traits and peculiarities 

 which are of value to the plant. 



t The fulfilment of these conditions implies, of course, flowers in 

 various stages of development — some with ripe anthers and imma- 

 ture stigmas, and some with mature stigmas and withered anthers. 



14 



