24 BOTANY. [CHAP. i. 



female elements are produced on different individuals of 

 the same kind) over self-fertilization, a further differen- 

 tiation took place, and the two sexes were either pro- 

 duced on distinct individuals of the same species, respec- 

 tively male and female, as in the willows and poplars, or 

 on different parts of the same plant as in the hazel, and 

 under such circumstances, the pollen being devoid of 

 spontaneous movement had to be transported to the 

 female by some outside agent, which in the above and 

 numerous other examples consisted of the wind, the 

 pollen being blown when mature from the male to the 

 female plant. Plants that utilize the wind as the agent 

 for bringing the pollen in contact with the ovules, or 

 female bodies requiring fertilization, are termed anemo- 

 philous. 



Anemophilous plants are often characterized by having 

 the flowers developed before the leaves, as the latter 

 would interfere with the pollen being blown on to the 

 stigma or special structure of the female part for receiv- 

 ing the pollen. The anemophilous method, although as 

 a rule securing the desired cross-fertilization, was a very 

 extravagant way of effecting that object, enormous quan- 

 tities of pollen having to be produced for the purpose of 

 securing fertilization by what may be termed a chance 

 method, and has been to a great extent superseded by 

 utilizing insects as the agents for conveying the pollen 

 from one plant to the stigma of another and thus securing 

 cross- fertilization . 



Having traced the origin of the highly differentiated 

 group of flowering plants from the lowly aquatic sea- 

 weed, it is necessary in the next instance to indicate 

 briefly the work done by the various specialized parts 



