240 



ESSENTIAL ORGANS — THE PISTIL. 



is denominated lobed, being one, two, three, four, or five lobed, 

 according to circumstances. In fig. 417 the nine carpels forming the 

 ovary, o, are divided by grooves; and in fig. 418 a transverse section 

 of the ovary of Fuchsia coocinea shows the four carpels which form 

 it. The changes which talie place in the pistil by adhesion, degenera- 

 tion, and abortion, are frequently so great as to obscui'e its composi- 

 tion, and to lead to anomalies in the alternation of parts. The pistil 

 is more liable to changes of this kind than any other part of the 

 flower. 



The carpels are usually sessile leaves, but sometimes they are 

 petiolate, and then are elevated above the external 

 whorls. This elevation of the pistil may in 

 general, however, be traced to an elongation of 

 the axis itself, in such a way that the carpels, 

 in place of being dispersed over it, arise only from 

 its summit. A monstrosity often occurs in the 

 Rose (fig. 419), by which the axis is prolonged, 

 and bears the carpels, /, in the form of alternate 

 leaves. Thus, by the union of the petioles of 

 the carpels, or by lengthening of the axis, the 

 pistil becomes sHpitate (stipes, a trunk), or sup- 

 ported, as in the Passion-flower, on a stalk (figs. 

 414, 416 g), called a gynophore (yuK)), pistil, 

 and poosM, I bear), or thecaphore (drixri, a case). 

 Sometimes the axis is produced beyond the 

 ovaries, and the styles become united to it, as 

 in Geraniacese and Umbelliferse. In this case 

 the prolongation is called a carpophore (xag^Js, 

 fruit, and fogiai, I bear). 



The ovules are developed on the inner side of the carpel where 

 the two edges of the carpellary leaves unite, and they are connected 

 to it by vascular bundles which proceed from below upwards, traverse 

 the carpel, and send a branch to each of the ovules. At the same 

 place there is a development of cellular tissue in connection with the 

 conducting tissue of the style and with the stigma. By the imion of 

 these tissues is formed the placenta, a cellular projection to which the 

 ovules are attached. Some restrict the term placenta to the point of 

 attachment of a single ovule, and call the union of placentas, bearing 

 several ovules, placentaries or pistillary cords. The part of the carpel 

 where the placenta is formed is the inner or ventral suture, correspond- 

 ing to the margin of the folded carpellary leaf, while the outer or dorsal 

 suture corresponds to the midrib of the carpellary leaf The placenta 



Fig. 419. Section of monstrous Hose, as figured at page 172, tlie axis of which is pro- 

 longed teyond the flower, and the envelopes removed to show the aboi-tive stamens, r. The 

 carpels, /, are attached alternately along the axis in the form of leaves, j), Aliortive floral 

 , Stamens in imperfect flower at the apex. 



419. 



