THE WALLFLOWER 103 



III. INTERNAL STRUCTURE AND DEVELOPMENT 

 OF THE REPRODUCTIVE ORGANS 



We use the term " reproductive organs " here in a 

 wide sense, to include all the parts of the flower, 

 although many of these are only of indirect service in 

 reproducing the plant. We do so because the sole 

 function of these organs is to form a sexually produced 

 embryo or young plant, and to send it into the world 

 as well equipped as possible for its future life. The 

 floral organs are only of service in so far as they con- 

 tribute to this end. 



We have already learnt the general arrangement 

 and outward appearance of the parts of the flower 

 (see p. 18) ; we will now consider the order and method 

 of their development. 



a. Development of the Flower 



The very young flower-bud arises from the stem as 

 a rounded outgrowth, which soon acquires a short stalk 

 (see Fig. 38). The calyx is the first of the floral organs 

 to appear. The anterior sepal takes the lead, appearing 

 as a crescent-shaped ridge of tissue (see Fig. 38, A, s a ) ; 

 next the two lateral sepals (s l ) appear together, and 

 lastly the posterior one, which lies next the main flower- 

 stalk (B, s p ) (see also diagram, Fig. 13, p. 23). When 

 the calyx has started its growth, the corolla begins 

 to develop. All the four petals show themselves 

 simultaneously, arising as small papillae immediately 

 within the calyx at the points corresponding to the 

 spaces between the sepals (see Fig. 38, C, p a and p p ). 



