88 PISTIL. 



Although some plants, like those above noticed, have their 

 pistils of one leaf, yet in most cases they consist of several 

 carpels, assuming a great variety of forms. It is of the first 

 importance, that the student study carefully all that relates 

 to the fruit, as it is from it that the most important distinc- 

 tions in classification are derived. It will be the most diffi- 

 cult as well as the most important subject to which his atten- 

 tion will be called. By perseveringly applying the principles 

 laid down, he will soon acquire a facility in examining, one 

 of the most beautiful fields of nature, which will abundantly 

 reward him for all his toil. 



104. When the ovary is composed of several carpels, 

 the carpels are arranged with the midrib placed outwardly, 

 and the margins turned inward towards the center, as seen 



in the transverse section of the Hibiscus, 

 fig. ]06, which is composed of five car- 

 pels, with their margins meeting in the 

 center, forming a central placenta, to 

 which the seeds are attached. The divi- 

 sions, which form the cells of the ovary, 

 are called dissepiments, and are of course, 

 from what we have before remarked, the 

 inflected laminae of the leaves ; and as 

 each carpel is naturally independent of the others, which com- 

 pose the ovary, it follows that the dissepiments, however 

 thin and membranous they may be in some cases, are in re- 

 ality double. All true dissepiments are necessarily vertical, 

 and never horizontal, since the inflected margins of leaves 

 could not unite in such a manner. The number of dissepi- 

 ments is always equal to the number of carpels of which the 

 ovary is composed, and the dissepiments are always alternate 

 with the stigmas. A simple ovary can have] no dissepiment. 

 Should any fruit be observed with dissepiment not reconcible to 

 the above principles, they are called spurious dissepiments. The 

 only common one of this character with which students will 

 meet is that occuring in cruciferous plants, as the Cabbage, 

 Turnip, &;c., in which the expansion of the placenta forms a 

 spurious dissepiment, stretching from one side of the ovary to 



the other. In some cases in which the 

 107y^ /'xl'^^'^^X o^'f^i'y is composed of several carpels, there 



exists no dissepiment. This arises from 

 one of two causes. In one case the 

 edges of the carpels are united without 

 being inflected much, if at all, as in the 

 Corydalis and Viola fig, 107, where the 



