THE ESSENTIAL ORGANS THE PISTIL. 



131 



Multilocular Ovary Placentation. When the carpels are firmly 

 and organically united by the surfaces of contact, we obtain the 

 type of a compound multilocular or many-celled ovary (fig. 248)*. 



Fig. 247. 



8 



Fig. 248. Fig. 249. Fig. 250. Fig. 251. 



Multilocular compound ovaries. 



Pig. 247. Ovary, styles, and stigmas of Malva. Fig. 249. 3-celled ovary of Lilium. 



Fig. 248. 2-celled ovary of Scrophulariaceae. Fig. 250. 3-celled ovary of Commelyna. 



Fig. 251. 4-celled ovary of Fuchsia. 



In these cases the sides of the constituent carpels are folded in- 

 wards, so as to meet in the centre, and thus form partitions be- 

 tween the chambers or loculi. The placental margins of the 

 infolded carpels are retroflexed, constituting central or axile pla- 

 centas. The partitions are called dissepiments, and are necessarily 

 double, being composed of the conjoined side-walls of contiguous 

 carpels. In such ovaries the dorsal sutures are in the outer wall, 

 while the ventral sutures meet in the centre (fig. 248). 



Examples of this kind of ovary are furnished by Liliacese (fig. 249) 

 and many other Monocotyledonous orders, by Ericaceae, Solanaceee, Scro- 

 phulariaceae, &c. In some cases the ventral sutures and placentas are not 

 directly confluent, but adhere to a central prolongation of the receptacle 

 running up between them, as in Geraniacese (fig. 276), &c. 



False or spurious dissepiments occur occasionally both in compound and 

 simple ovaries, consisting of membranes or plates developed from the pla- 

 centa or from the dorsal suture, and subdividing the originally single 

 cavity formed by individual carpels. Thus in Linum the 5-carpellary 

 ovary would have five loculi, were it not that a spurious dissepiment 

 extends inwards from the dorsal suture to the placenta in each loculus, 

 and divides the ovary into ten loculi. In Astragalus (fig. 252) the simple 

 ovary is divided by" the inflexion of the dorsal suture, and in Datura 

 Stramonium a false septum is formed in each of the loculi of the ovary. 

 The transverse false septa found in various Leguminous ovaries, such as 

 Cathartocarpus &c., are likewise outgrowths from the walls of the carpel. 



Unilocular compound Ovary. If the carpels are not inflexed, 

 but cohere by their contiguous margins, they form a hollow case 



* The terra cell, though commonly used, is objectionable, as leading to confu- 

 sion with the cells which make up the tissues of the plant. On this account the 

 word loculus is preferable. 



