THE FLOWER OF THE HIGHER SEED-PLANTS 155 
united and the stigmas separate or at least lobed, so as to 
show of how many carpels the pistil is made up (Figs. 99, 
100). Even when there is no external sign to indicate the 
compound nature of the pistil, it can usually be recognized 
from a study of a cross-section of the ovary. 
184, Locules of the Ovary; Placentas. — Compound 
ovaries very commonly consist of a number of separate 
chambers known as locules. 
Fig. 118, B, shows a three- / 
loculed ovary seen in cross- & 
section. The ovules are Ce) 
A B C 
not borne indiscriminately 
by any part of the lining of Fie. 113. Principal Types of Placenta. 
the ovary. In one-loculed A, parietal placenta; B, central placenta; 
pistils they frequently grow C, free central placenta; A and B,trans- 
- ‘ : verse sections; C, longitudinal section. 
in a line running along one 
side of the ovary, a8 in the pea pod (Fig. 146). The ovule- 
bearing line is called a placenta; in compound pistils there 
are commonly as many placentas as there are separate 
carpels joined to make the pistil. Placentas on the wall 
of the ovary, like those in Fig. 113, A, are called parietal 
placentas; those which occur as at B, in the same figure, 
are said to be central; and those which, like the form rep- 
resented in C of the same figure, consist of a column 
rising from the bottom of the ovary-are called free central 
placentas. 
185. Superior, Half-Inferior, and Inferior Ovaries. — 
When, as in the flower of Fig. 98, the receptacle is rounded 
or club-shaped and the floral organs arise from it in suc- 
cessive sets, the flower is said to be hypogynous, from two 
Greek words, here applied to mean under the pistil, and the 
ovaries are said to be superior (Fig. 114, I). 
