CHAP, i.] PLANT ARCHITECTURE. 31 



(4) The pistil, or female organ of the flower, is again 

 situated within the ring of stamens, and occupies the 

 apex of the floral axis. It consists of one or more 

 structures called carpels, that in the majority of flower- 

 ing plants form closed cavities, the ovaries, that contain 

 the ovules, or young unfertilized reproductive bodies. 

 After fertilization the ovules undergo great structural 

 changes the result of fertilization and are called seeds, 

 the ovary or protective portion then also undergoes 



Fig. 7. Diagrammatic section of a typical flower showing the 

 various parts in their relative positions. I., calyx; II., corolla; 

 III., stamen, consisting of filament and anther ; IV., pistil, consisting 

 of a lower swollen portion, the ovary, and a terminal knob-like part, 

 the stigma, supported on a stalk, the style. 



certain changes and becomes the fruit. There are two 

 primary divisions of flowering plants or Phanerogams 



(1) Oymnosperms, including the pines, firs, cedars, 

 yews, etc., characterized by having the ovules naked, 

 that is, not contained within an ovary. In the members 

 of this group fertilization is direct, the pollen coming di- 

 rectly in contact with ovule. 



(2) Angiosperms. The majority of flowering plants 

 are included in the present division, characterized by 



