26 NATURE STUDY. 



place will these rudimentary seeds begin to develop into 

 real seeds, capable of forming new plants. 



It is a law of nature that better seeds are produced 

 when the pollen from one flower is carried to the stigma 

 of another flower of the same kind ; that is, when there 

 is what is called cross-fertilization. Seeds may be formed 

 when the pollen of a flower gets on and pushes into the 

 pistil of the same flower, but this process of self-fertili- 

 zation is not apt to produce as healthy, vigorous seeds or 

 plants as does cross-fertilization. It is to the interest 

 of most flowers, including the dandelion, to prevent self- 

 fertilization, and secure cross-fertilization as much as is 

 possible. 



We shall find that the structure and changes in co- 

 rolla, stamens, and pistil are arrangements or adapta- 

 tions to insure cross-fertilization, if possible ; otherwise, 

 self-fertilization. In cross-fertilization the pollen is most 

 commonly conveyed from the stamens of one flower to 

 the stigmas of other flowers, either by insects or the 

 wind. The dandelion hires the insects to carry her 

 pollen from flower to flower. 



The corolla has the special duty of attracting the 

 insects by its bright color (one reason why the blossom 

 is pushed up above the grass), and by the honey, or 

 nectar, at its base. From the nectar and from the pol- 

 len, of which the dandelion and other flowers produce 

 much more than they can use, the provident insects get 

 their store of food. The bright-colored corolla is the 

 signboard telling where these can be found. In getting 

 them the insects brush off and carry on the hairs on 



