THE WALLFLOWER 25 



The middle of the flower is occupied by the pistil 

 This is a nearly cylindrical hollow body, green in 

 colour, tapering a little towards the top, and sur- 

 mounted by a forked outgrowth. The lower thicker 

 part, which occupies more than three-quarters of the 

 whole length, is the ovary, and the forked outgrowth 

 at the top of all is the stigma, while the short 

 tapering portion which connects the two is the style 

 (see Figs. 9, 10, and 11). 



The hollow ovary is divided lengthways into two 

 compartments by a membrane called the septum. 

 This membrane marks the boundary between the two 

 carpels, the name given to the floral leaves of which 

 the pistil is composed. We see, then, that the two 

 carpels are so placed as to lie opposite the two inner 

 lateral sepals. Within the ovary are the young seeds, 

 or ovules, as they are called at this early stage. They 

 grow on the walls of the ovary adjoining the septum. 

 As, however, we are only dealing with external 

 characters at present, we will postpone any further 

 examination of the interior of the ovary and of the 

 ovules. 



The ovules only develop into the seeds after 

 fertilisation, which is brought about by the pollen. 

 In order that the ovules may become ripe seeds, 

 which can grow into young plants, it is necessary 

 that the pollen should come into contact with the 

 stigma of the pistil. The whole process of fertilisa- 

 tion will be described later on, when we have made 

 ourselves acquainted with the internal structure of 

 the floral organs (see p. 122). 



