MOEPHOLOGY OF REPEODUCTIVE OKGANS 19.S 



titians as there are component carpels ; or it may have only one 

 cavity. These differences have an important influence upon 

 the attachment of the ovules, as will be aftervi'ards seen when 

 speaking of plaoentation. If we have three free carpels placed 

 side by side (fig. 415, a), each of these possesses a single cavity 

 corresponding to its ovary, so that if we make a transverse sec- 

 tion of the whole, 6, we necessarily have three cavities, each of 

 which is separated from those adjoining it by twa walls, one being 

 formed by the side of its own ovary, and the other by that of the 

 one next to it. But if these three carpels, instead of being 

 distinct, are united by their ovaries as in fig. 416, a, so as to form 

 a single ovary, the latter must necessarily also have as many 

 cavities as there are component carpels, h, and each cavity must 

 be separated from those adjoining it by a wall which is called a 

 dissepiment or partition. Each dissepiment must be also com- 

 posed of the united sides of the two adjoining ovaries, and be 

 consequently double. 



In the normal arrangement of the parts of the ovary, it ^^'ill 

 necessarily happen that the styles (when they are distinct) 

 must alternate with the dissepiments, for as the former are 

 prolongations of the apices of the blades of the oarpellary leaves, 

 while the latter are formed by the union of their margins, the 

 dissepiments have the same relation to the styles as the sides 

 of the blade of a leaf have to its apex ; that is, they must be 

 placed right and left of them. 



The cavities of the compound ovary are called cells or loculi, 

 and such an ovary as that just described would be therefore 

 termed three-celled or trilooular, as it is formed of three united 

 ovaries. All dissepiments which are not formed by the united 

 walls of adjoining ovaries are termed spurious or false. It 

 follows, therefore, that a single carpel can have no true dissepi- 

 ment, and is hence, under ordinary and normal circumstances, 

 u/nilocular or one-celled. 



From the preceding observations it follows that when ovaries 

 which are placed side by side cohere, as in fig. 410, and form 

 a compound ovary, the dissepiments must be vertical, and eqiial 

 in number to the ovaries out of which that compound ovary is 

 formed. "When a compound ovary is composed, however, of 

 more than one whorl of ovaries placed in succession one over 

 the other, as in the Pomegranate, horizontal true dissepiments 

 may be formed by the ovaries of one whorl uniting by their 

 bases with the apices of those placed below them [fig. 551). 

 We have just observed that all dissepiments are said to be 



VOL i. 



