CHAPTER XIV 



THE PROMISE OF THE PLAXT THAT 18 TO BE 



. . . Fruit and seed, 



New loosed from thorn-bush, tree, and Haunting weed, 

 And now by wing, or scale, or plume up-borne, 

 Fare forth on pilgrimage. 



WHEX water, wind, or animal (or, it ma}* be. the unaided plant) 

 has fulfilled its function as an agent of pollination, the true 

 process of fertilization begins. The outcome of fertilization is the fruit. 



In popular language the term u fruit" may mean many things, but 

 botanists usually confine it to the ripened pistil or ovary of a flower. 

 Possibly this use of the term is rather too exclusive. Kerner would 

 extend the definition to " everything which undergoes alteration after 

 fertilization either in the flowers or flowering axis," and urges that as 

 the changes in question are " for the purpose of promoting the interests 

 of the embryo," whatever participates in this object is the fruit. However, 

 not to appear singular, we will abide by the definitions of the text-books, 

 and take it that a fruit is a ripened and developed ovary. 



How does this ripening and development take place ? The accom- 

 panying figures will help us to 

 understand the process. Fig. 570 

 represents an ideal section through 

 a uniovular ovary just after pollin- 

 ation, a is the stigma, upon which 

 are six pollen-grains. The style (6) 

 widens into the ovary (cc), which 

 contains a single inverted ovule (d) 

 the latter not shown in section. 

 We speak of the ovule as inverted 

 because the rnicropyle (g) is not at 

 the apex of the ovule, but, by a 

 twisting round of the whole ovule, 

 is brought close to the funide or 

 point of attachment (/).* 



FIG. 569. WHITE WATER-LILY (Castalia alba). * This is the commonest form of ovule, 



and is described as anatropoiis. It must 

 be carefully distinguished from the bent 



A transverse section of the ovary, showins the ovules in the 

 carpels. 



464 



