116 :t5otan^ 



out for us the facts that concern the fertilization of 

 the ovules. What are these facts ? 



I. The pollen of the stamen must reach the ovules 

 through the stigma of the pistil. 



II. The most vigorous and perfect seed is secured 

 when the pollen from one flower is conveyed to the 

 pistil of some other flower, rather than to its own 

 pistils. The ovules become better seed if the}^ are 

 fertilized from blossoms borne on a different root. 



III. Nature has many curious contrivances to 

 prevent pollen from reaching j^istils contained in 

 the same corolla as the anthers from which it came. 

 For instance, the anthers and stigma in some flowers 

 are so situated that the pollen cannot pass from one 

 to another; in many other cases the stamens and 

 pistils do not ripen in the same flower at the same 

 time. 



IV. The most wonderful arrangements have been 

 made to secure the conveyance of pollen to distant 

 blossoms. 



V. Unless pollen is conveyed to plants of the same 

 kind as that producing the pollen, seed will not be 

 fertilized. Lily pollen cannot fertilize the ovules of 

 roses ; buttercup pollen is wasted on dandelions. 



VI. The animal world, which is maintained by 

 the vegetable world, must provide the carriers for a 

 large part of this pollen, for the flowers are root-fast. 



