148 



ELEMENTS OF BOTANY. 



three-celled ovary, seen in cross-section. The ovules are not 

 borne indiscriminately by any part of the lining of the ovary. 

 In one-celled pistils they frequently grow in a line running 

 along one side of the ovary, as in the pea pod, Pig. 176. The 

 ovule-bearing line is called a placenta; in compound pistils 

 there are commonly as many placentas as there are separate 

 pistils joined to make the compound one. Placentas on the 

 •wall of the ovary, like those in Fig. 132 A, are called parietal 

 placentas; those which occur as at B, in the same figure, are 



stig. 



Fig. 125. - Tubu- ' ^^<^- 127- " P^'-ts 



lar Corolla, from FiG. 126. — Labiate of a Stamen. 



Head of Baclie- or Eingent Corolla a, filament; 6, 

 lor's Button. of Dead Nettle. anther. 



Fig. 128. — Parts of the 



Pistil. 



ov., ovary ; sty., style ; 



stig., stigma. 



said to be central, and those which, like the form represented 

 in C of the same figure, consist of a column rising from the 

 bottom of the ovary, are called free central placetitas. 



185. Union of Separate Circles. — The members of one of 

 the circles of organs of which the flower is composed may 

 join each other or become adnate, adherent, or consolidated. 

 In Pig. 117 the calyx-tube is adnate to the ovary. In this 

 case the parts of the flower do not all appear to spring from 

 the receptacle. Fig. 133 illustrates three common cases as 

 regards insertion of the parts of the flower. In I they are 



