f>04 



BOTANY 



VENTRAL SUTURE, while the midrib of the carpel forms the DORSAL 

 SUTURE. In syncarpous ovaries the ovules are similarly borne on the 

 margins of the coherent carpels. The placentation is termed PARIETAL 

 when the placentas form projections from the inner surface of the 

 wall of the ovary (Fig. 477 D). If the margins of the carpels project 



Fm. 475. jtlthtifa rtjlii-iiuili*, Hower cut through 

 longitudinally ; a, epicalyx : l>, calyx ; c, 

 corolla ; (?, androecium. (After 13ER<; and 

 SCHMIDT, magnified.) 



KH.. 47(1. Transverse section of an ovary of 

 Delphinium Ajatis, showing ovule placed 

 horizontally; .--, ovule; p, placenta; o, 

 ; wall of ovary ; r. vascular bundles, (x 18.) 



farther into the ovary, and divide its cavity into chambers or loculi, 

 the placentas are correspondingly altered in position, and the 

 placentation becomes AXILE (Fig. 477 B). In contrast to such TRUE 

 SEPTA, formed of the marginal portions of the carpels, those that 

 arise as outgrowths of the surface or sutures of the carpels, as in 

 the Cruciferae, are called FALSE SEPTA. By the upgrowth of the 



Flc. 477. Transverse sections of ovaries. A, l.olirlia ', /.'./'/"; >/; ' '. A7c/n</, /' 

 D, 1'as.fiflinii ; t il. placenta ; , ovules. (After LE MAOUT and DKCAISXK.) 



floral axis in the centre of the ovary what is known as FREE CENTRAL 

 PLACENTATION comes about. The projecting axis cannot be sharply 

 distinguished from the tissue of the carpels. The septa, which 

 were originally present, are arrested at an early stage of develop- 

 ment or completely disappear, so that the ovules are borne on the 

 central axis covered with carpellary tissue and enclosed in a wall 

 formed by the outer portions of the carpels. 



