GROSS ANATOMY OF FLOWERING PLANTS. XXxiil 
Simple Pistil.—In the simple pistil the ovules actually grow 
out from the united margins (the ventral suture) of the carpophyll; 
the internal ridge or projection upon which they are borne is the 
placenta. Sometimes the ovules are erect—i.e., they grow upward 
from the bottom of the ovary—anud when single appear to be di- 
rect continuations of the flower-axis. Suspended ovules—i.e., 
those growing from the apex of the ovary-cavity—are also com- 
mon, (Fig. XXXII) 
Compound Pistil.—In compound pistils the coalescence may be, 
on the one hand, of closed carpels, and on the other of open car- 
pels. In the former case the pistil has generally as many loculi 
(cavities or cells) as there are carpels; this is expressed by the 
5 
Fig. XXXIII.—Cross-sections of compound pistils: 1, 2, 3, 4. unilocular; 5, 
bilocular; 6 and 7, trilocular; 8, quadrilocular. 1, 2.3. with parietal placente; 
4, with a free central placenta; 5 to 8, with axile placentas, 
terms bi-, tri-, guadri, and so on to multi locular (5 to 8, Fig. 
XXXIII). Such pistils have avile placente—i.e., they are gathered 
about the axis of the ovary. In the case of compound pistils 
formed by the coalescence of open carpels, the margins only of 
the latter unite, forming a common ovary-cavity (unilocular, 
1, 2, 3, Fig. XXXII); here the placenta gencrally occur along 
the sutures, and are said to be parietal—i.e. on the walls. 
Between such unilocular pistils and the multilocular ones de- 
scribed above there are all intermediate gradations. In one series 
of gradations the placente project farther and farther into the 
