268 FLOWERS 



you have been told that the embryo in the seed is the 

 direct result of a sex process. (See page 58). Why, then, 

 is a flower not a sex organ? 



This matter would not be worth discussing if it were 

 merely a question of how we are to use the expression 

 sex organ, but it is a question of much more than that. 

 It is a question of your understanding or misunderstanding 

 a very fundamental thing in plant Kfe. 



The sex process is the union of two cells into one which 

 develops into a new individual, and a sex organ is an organ 

 which produces one or the other of these two kinds of sex 

 cells whose union constitutes the sex process. Now those 

 cells from whose union the embryo of seed plants arises are 

 not cells of the flower. If they were, the flower would be a 

 sex organ. Since they are not, the flower is not a sex 

 organ. 



Any single cell of a plant which gives rise to a new 

 individual is called a spore. All plants produce spores. 

 The young grains of pollen are spores. 



An individual which arises from a single cell of its parent 

 is a new generation; it is not, strictly speaking, a part of 

 its parent, even though it remains in the body of its parent. 

 Spores give rise to new generations. 



The new generation to which the pollen grain gives rise 

 is contained within the grain; it consists of but a few 

 cells, but it is none the less a new generation. The pollen 

 grain after pollination gives rise to a structure called the 

 pollen tube. This pollen tube grows down into the very 

 center of the flower, and the contents of the pollen grain 

 move down through it. (See Figure 95.) In the center 

 of the flower the pollen tube reaches another individual, 

 another hidden generation, which has also resulted from the 



