STRUCTURE OF THE FLOWER AND ITS ORGANS. 147 
called the stigma. These parts are all shown in Fig. 128. 
In many pistils the stigma is borne directly on the ovary, as 
in Fig. 145. 
182. Union of Stamens with each Other.— Stamens may be 
wholly unconnected with each other or distinct, or they may 
cohere by their filaments into a single 
group, when they are said to be monadel- 
phous, of-one-brotherhood, Fig. 129, into 
two groups (diadelphous), Fig. 130, or 
into many groups. In some flowers the 
stamens are held together in a ring by 
their coherent anthers, Fig. 131. 
183. Union of Pistils. — The pistils 
may be entirely separate from each other, 
distinct and simple as they are in the 
buttercup and the stonecrop, or several 
may join to form one compound pistil of 
more or less united carpels. In the 
latter case the union generally affects the Fre. 123. —Salver-Shaped 
ovaries, but often leaves the styles sep- eee a cada 
arate, or 1t may result in joining ovaries 
and styles, but leave the stigmas separate 
or at any rate lobed, so as to show of how 
many separate carpels the compound pis- 
til is made up. Even when there is no 
external sign to show the compound 
nature of the pistil, it can usually be 
recognized from the study of a cross- 
section of the ovary. 
184. Cell of the Ovary; Placentas. —Compound ovaries 
are very commonly several-celled, that is, they consist of a 
number of separate cells’ or chambers. Fig. 132 B shows a 
Fic. 124. — Wheel-Shaped 
Corolla of Potato. 
1 Notice that the word cell is here used in an entirely different sense from that 
in which it has been employed in the earlier chapters of this book. As applied to the 
- Ovary, it means a chamber or compartment. 
