100 BOTANY. 



dorsal suture, and nearly reaching the center of the seed- 

 vessel. 



Fig. 309 shows a similar false partition not quite so 

 much extended. 



Fig. 310 is a section across the middle of an ovary, and 

 Fig. 311 is a section across the upper part of the same 



FIG. 307. FIG. 308. FIG. 309. 



ovary. The partitions that appear in one and are not seen 

 in the other must be false they can not be formed by 

 the sides of adjacent carpels. 



In Fig. 312 the placentae are parietal, but a membrane 

 is formed, reaching across the ovary, and forming a false 



FIG. 310. FIG. 311. FIG. 312. 



dissepiment. These false dissepiments, you see, are de- 

 veloped, in some cases, from the dorsal suture ; in others, 

 from the placentae. 



It may sometimes be difficult to decide between true 

 and false dissepiments ; but, as your knowledge of plants 



