PISTIL, 79 



pistil ; in others no point can be detected, by observation, that 

 corresponds in appearance to the stigmatic surface. The central 

 part of the stigma consists of a more hix tissue which leads di- 

 rectly to the ovary, and is called the conducting tissue. 



128. The style (Fig. 127, b) is a vascular organ, varying in 

 length, supported by the ovary, and supporting the stigma. It 

 is generally considered an unessential organ ; but Raspail says 

 that the style penetrates the ovary and becomes the placenta, 

 which would render its presence always necessary; but this is 

 in opposition to all other botanists, so far as we know, the pla- 

 centa beinof considered the union o( the eda^es of the folded 

 leaves composing the ovary. The style is sometimes articulated 

 to the summit of the ovary, and sometimes forms a continuation 

 of it. Although the style usually rises from the summit of the 

 ovary, yet in some cases it does not. In the Lahiatoe it comes 

 from the base, and in othei's from the side. These apparent 

 variations are produced by the unequal development of the parts 

 of the ovary ; one side being extended more than the other, 

 would, of course, turn the summit to the least developed side. 



I2&« The ovary (Fig, 127, a) is the thickened base of the 

 pistil, and is that part of the organ containing the ovules, and 

 becomes the fruit in maturity, whatever ma}^ be its form. The 

 ovary, when the pistil is composed of a single leaf, is formed by 

 the folding of the leaf with the upper surface inward and united 

 by its edges, the lamina of the leaf forming the ovary. This 

 arrangement is well exhibited by the PeacJi. The furrow, which 

 is always seen running from the apex to the base of this fruit, 

 on one side, is the united margins. The midrib on the opposite 

 side is undistinguishable on the surface, but by dissection the 

 vessels will be found larger on that side, and running more di- 

 rectly from the base to the apex. 



I30« The j^dcbcenta is the union of the two margins ^'^^'*- 

 of the carpels, and bears the ovules, which in maturity 

 become the seed. By carefully breakicg the stone of 

 the Peach, we shall find the kernel attached to that 

 side of the cavity which corresponds to the depressed 

 line on the surface, showing that the kernel or nucleus 

 derived its origin and support from that side which is 

 formed hj the margin of the leaf. The Cherry is an- 

 other example of a monocarpelous pistil. (Fig. 128.) 



131. Althoufyh some plants, like those above noticed, „ 

 nave their pistils or one ieai, yet in most eases they louspistii. 



What is the oondu-eting tissue ?— 128, What is the style ?— 529- Wli«t 

 is the ovary? How is it formed when thp pistil is composed of a singla 

 leaf? When exhibited ? Explain tha pexich,— 330- What is tlic plac^Mita ' 



