208 



ESSENTIAL ORGANS. THE PISTIL. 



mediately on the ovary, and is then called sessile, as in the Tulip and 

 Poppy, (fig. 409), or is elevated on a stalk called the style, interposed 

 between the ovary and stigma. The style is not neccessary for the per- 

 fection of the pistil. Sometimes it becomes blended with other parts, 

 as with the filaments of the anthers in the column of Orchidacese. 



430. Like the other organs, the pistil consists of one or more modi- 

 fied leaves, which in this instance are called carpels ^x^6;, fruit). 

 The analogy of carpels to leaves may be deduced from their similarity 

 in texture, and in venation, from the presence of stomata, hairs, and 

 glands; from their resemblance to leaves in their nascent state ; from 

 then- occasional conversion into true leaves, as in Lathyrus latifolius ; 

 and from the ovules corresponding in situation to the germs or buds 

 found in some leaves, as those of Bryophyllum calycinum. When a 

 pistil consists of a single carpel it is simple, a state usually depending 

 on the non-development of other carpels; when it is composed of 

 several carpels, more or less united, it is compound. In the first- 

 mentioned case, the terms carpel and pistil are synonymous. Each 

 carpel has its own ovary, style (when present), and stigma, and is 

 formed by a folded leaf, the upper surface of which is turned inwards 

 towards the axis, and the lower outwards; while at its margins are 

 developed one or more buds called ovules. That this is the true nature 

 of the pistil may be seen by examining the flower of the double- 

 flowering Cherry. In it no fruit 

 is produced, and the pistil con- 

 sists usually of sessile leaves (fig. 

 371), the limb of each being 

 green and folded, with a narrow 

 prolongation upwards, s, as if 

 from the midrib, n, and ending 

 in a thickened portion. When 

 the single-flowering Cherry is 

 examined, it is found that, in 

 place of folded leaves, there is 

 //* a single body (figs. 372, 373), 

 the lower part of which is 

 enlarged, forming the ovary, o, 

 and containing a single ovule, 

 <7, attached to its walls, with a bundle of vessels, fn, entering it, a 



Fig. 371. Carpellary leaf of the double-flowering Cherry. In this plant the pistil is composed 

 distinctly of one or more leaves folded inwards. I, Lamina or blade of the leaf or carpel, s, 

 Prolongation of the midrib, n, representing the style, and ending in a circular thickened portion 

 equivalent to the stigma. 



Fig. 37:!. Pistil or carpel of the single-flowering Cherry in its normal state, o, Ovary. 

 t, Style, s, Stigma, 



Fig. 373. The same cut vertically, to show the central cavity of the ovary, o, with the ovule, 

 g, suspended from its wall at a point where a bundle of nourishing vessels, / n, terminates. 

 t, Style traversed by a canal, c, which runs from the stigma, s, to the cavity of the ovary. 



