STATING THE CASE. 



37 



poured out, and the ovules are now said to be 

 fertilised. Each ovule begins to increase in size — 

 in other words, to groiv. The top of the pistil 



Fig. 14. — Highly-magnified section of the pistil of a flower, showing the pollen- 

 grains shooting forth tubes which penetrate the tissue. 



usually withers, and the stamens always ; and 

 the vital energy of the plant, or what is left after 

 expending so much in insuring cross -fertilisation, is 

 thrown into the act of developing the ovules into seeds. 



