■12 THE FLOW'EK. 



axis, while the lower surface becomes the outer. By this aiTangemcnt the two 

 edges of the carpel often appear like sutures (Lat. sutura, a seam), of which the 

 outer, formed hy the midrib, is called the dorsal, and the inner, formed by the 

 united margins, the ventral. 



a. This view of the jjistil is remarkably confirmed and illustrated by the flowers 

 of the douljlu cherry, where the pistil may be seen in every degree of transition, 

 reverting towards the form of the leaf. This carpcUary leaf (Fig. 10; 9) stands in 

 the place of tlie ])istil, having the edges infolded towards each other, the midrib 

 greatly jw-olongcd, and a little dilated at the apex. 



b. If this be c(jmpared with the pistil of the chen-y, seen in the figure, no donbt 

 can be entertained that the two sides of the leaf con-espond to the walls of the 

 ovary, the margins to the ventral suture, the prolonged midrib to the dorsal 

 suture, and the style and the dilated summit to the stigma. Sometimes tlie 

 tlower contains two such leaves, which always, present theii* concave faces towards 

 each other, as seen in the figure. This coiTesponds with the position of the true 

 carpels, in which the ventral sutures of each are contiguous. 



c. Many other plants, as the rose. Anemone, Eanunculus, &c. exhibit similar 

 transfonnations of the pistil, so that there can be no doubt that the carpel is 

 formed upon the same plan in all plants. ' The ovary, therefore, is the blade of a 

 leaf, the style the lengthened midrib, and the stigma the dilated and denuded apex of 

 the same.'' 



85. From tliis doctrine of the stntcture of the single carpel, 

 the student will be able and expected to deiiionstraie 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). 



b. 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. 



d. Again, the single carpel can have no true chssepiment. If 

 any ever occur, it is regarded as an anomaly, and called spurious. 

 Ex. flax (Fig. 11). 



86. Those propositions are true only when each carpellary 

 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. pea. 



