OVULES. 43 
87. The placente are developed at each of the two edges of 
the carpellary leaf. If these edges be in their normal condi- 
tions, that is, united, there will be apparently but one placenta 
to the carpel, and that central. But if the edges be separate, 
there will necessarily be two placente to each carpel, the one 
to the right and the other to the left of the dorsal suture and 
style. They are then said to be parietal ( parzes, a wall). 
FIG. 11.—1, Cross section of a one-celled, three-carpelled ovary with parietal placentz, 
the dissepiments partially obliterated ; 2, dissepiments wholly obliterated; 3, dissepiments 
obliterated, showing a free central placenta; 4, a five-celled ovary with 5 false dissepiments, 
as in the flax; 5, vertical section of an ovary with parietal placente ; 6, with free central pla- 
cente ; 7, an amphitropous ovule; 8, vertical section of the same; a, funiculus; }, raphe; 
c, chalaza; d, nucleus; e, secundine; , primine; g, micropyle; 9, anatropous ovules at- 
tached to the ovary. : 
88. But the placente are sometimes found in the common 
centre when there are no dissepiments (Fig. 11; 3,6). This 
anomaly, which is called a free central placenta, is thus ex- 
plained. The dissepiments were at first actually formed in the 
usual manner, but afterwards, by the rapid expansion of the 
shell, they were torn away and obliterated. 
a. As the ovules are always developed by the placente, they, of course, grow 
out of the margins of the carpellary leaf, and are, therefore, understood to be 
analogous to buds. For, in the Bryophyllum, and some other plants, the true 
leaves do habitually develop buds at their margins (Fig. 10; 8), and in the mign- 
ionette the ovules themselves have been seen transformed into leaves. 
89. The ovules are almost always enclosed in the ovary. In 
the mignionette they are partially naked, and in the fir tribe, 
Conifer, entirely so, the carpellary leaf being open or wanting. 
