THE PISTILS, OE GYNOECIUM. 



105 



516. The parts of a simple pistil arc three, the ovary at base, the 

 stigma at the summit, and the style, intervening. Like the filament 

 the style is not essential, and when it is wanting, the stigma is sessile 

 upon the ovary, as in crowfoot. In order to understand the relation of 

 these parts we must needs first study 



516. The mobphologt of the pistil. As before stated, (§ 380), the 

 pistil consists of a modified leaf called a carpel {iiap-Kbg, fruit), or carpel- 

 lary leaf. This leaf is folded together (induplicate) toward the axis, so 

 that the upper surface becomes the inner, while the lower becomes the 

 outer surface of the ovary. By this arrangement two sutures or seams 

 will be formed, the dorsal, at the back by the midvein, the ventral, in 

 front by the joined margins of the leaf. 



885, Simple pistil of Strawberry, the stylo lateral. 388, Simple pistil of Crowfoot, cut to 

 show the ovule. 3S0, Simple pistil of the Cherry. 881, Vertical section showing the ovule (o), 

 style (fi), stigm.i (a). 882, Cross-Section of the same. 384, Compound pistil of Spring-beauty. 

 333, Cross-section of the same showing the 3 cells of the ovary. 378, Expanded carpellary leal 

 of the double cherry. 379, The same partly folded as if to form a pistil. 



517. Illustration. This view of the pistil is remarlcably confirmed and iHua- 

 trated by the flowers of the double cherry, where the pistil may be seen in every 

 degree of transition, reverting toward the form of a leaf. This carpellary leaf 

 stands in the place of the pistil, having the edges infolded toward each other, the 

 midvein prolonged and dilated at the apex. 



518. If this be compared with the pistil of the cherry seen in the figure (378, 

 379), 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 su- 

 ture, and the lengthened apex to the style and stigma. Sometimes tlie flower con- 

 tains two such leaves, which always present their faces toward each other. This 

 corresponds to the position of the true carpels, in which the ventral sutures of both 

 are contiguous. 



519. The doctkine DBDtrcBD. Many other plants, as the rose. Anemone, E'anun- 

 culus, flowering almond, exhibit similar transformations of the pistil, making it prob- 

 able that it is formed upon the same plan in all plants. The ovary, therefore, is the 

 blade of a leafj folded into a sack : the style is the lengthened apex folded into a 

 tube ; the stigma, a thickened and denuded portion of the upper margin of the 

 leaf. 



