380 



DISSEPIMENTS. 



[BOOK j. 



will be opposite the placentae m, 1 3 formed by the cohesion of 

 the contiguous margins of the carpels A and B. 



5. A single carpel can have no true dissepiment. 



6. The dissepiment will alternate with the stigma : for the 

 stigma is at the extremity of the carpellary leaf, or of the 

 dorsal suture of the carpel j and the sides of either of these 

 (which form dissepiments) will be right and left of the stigma, 

 or in the same position with regard to the latter organ as the 

 sides of the lamina of a leaf to its apex. Let the triangle a b c 



fig. 131. 

 @ d 



represent a transverse section of a three-celled ovary, of 

 which d, e } f are the dissepiments. The stigmas would occupy 

 a position equal to that of the spaces s, s, s, and would conse- 

 quently be alternate with d, e, f, the dissepiments : they 

 could not possibly be placed opposite d, e, /, upon any prin- 

 ciple of structure with which we are acquainted. This law 

 proves that neither the membrane which separates the two 

 cells of a cruciferous siliqua, nor the vertical plate that 



