42 THE FLOWER. 
axis, while the lower surface becomes the outer. By this arrangement the two 
edges of the carpel often appear like sutures (Lat. sutura, a seam), of which the 
outer, formed by the midvein, is called the dorsal, and the inner, formed by the 
united margins, the ventral. 
a. This view of the pistil is remarkably confirmed and illustrated by the flowers 
of the double cherry, where the pistil may be seen in every degree of transition, 
reverting towards the form of the leaf. This carpellary leaf (Fig. 10; 9) stands in 
the place of the pistil, having the edges infolded towards each other, the midvein 
greatly prolonged, and a little dilated at the apex. 
b. If this be compared with the pistil of the cherry, seen in the figure, no doubt 
can be entertained that the two sides of the leaf correspond to the walls of the 
ovary, the margins to the ventral suture, the midvein to the dorsal suture, and 
the lengthened summit of the leaf to the style and stigma. Sometimes the 
flower contains two such leaves, which always present their concave faces towards 
each other, as seen in the figure. This corresponds with the position of the true 
carpels, in which the ventral sutures of each are contiguous. 
c. Many other plants, as the rose, Anemone, Ranunculus, &c. exhibit similar 
transformations of the pistil, so that there can be no doubt that the carpel is 
formed upon the same plan in all plants. Zhe ovary, therefore, is the blade of a 
leaf; the style, the lengthened apex ; and the stigma, a thickened and denuded portion 
of the upper margin of the leaf: 
85. From this doctrine of the structure of the single carpel, 
the student will be able and expected to demonstrate many 
propositions like the following. 
a. First. A compound ovary consists of a whorl of carpellary 
leaves, their united edges all meeting in the centre, and the 
cohering sides forming a kind of radiation from it (Fig. 9). 
6. Second. There must be as many cells as there are carpels. 
c. Third. The partitions between the cells, that is, the dis- 
sepiments (dissepio, to separate,) must each be double; they 
must be vertical; they must be equal in number to the carpels, 
and alternate with the stigma, which is also double. 
d. Again, the single carpel can have no true dissepiment. If 
any ever occur, it is regarded as an anomaly, and called spurious. 
Ex. flax (Fig. 11). 
86. These propositions are true only when each capiclinier 
leaf appears in its normal condition, that is, with its two edges 
mutually united. But cases occur where only the margins of 
adjacent leaves are united (Fig. 11; 1, 2,3). In this case there 
will be no dissepiments, and the compound ovary will, of course, 
become one-celled. Ex. Primula, Gentiana, 
