238 



ESSENTIAL OEGANS — THE PISTIL. 



it is placed on a part of the column called the gynizus (yuvvj, pistil, 

 and 1^,01, I sit). It is composed of cellular tissue more or less lax, 

 often having projecting cellules in the form of papillse (fig. 410, 2), 

 or of hairs (figs. 413, 3 ; 446 s), and at the period of fertilisation 

 exuding a viscous iiuid, which retains the grains of pollen, and causes 

 the protrusion of tubes. 



A pistil is usually formed by more than one carpel. The carpels 

 may be arranged like leaves, either at the same or nearly the same 

 height in a verticil (figs. 414, 415), or at diflferent heights in a spiral 

 cycle (fig. 337 c). When they remain separate and distinct, thus show- 

 ing at once the composition of the pistil, as in Caltha, Eanunculus, 

 Hellebore, and Butomus (fig. 415), the term apocarpous (k'tto, separate, 

 and xag'jrhg, fruit) is applied. Thus, in Crassula rubens (fig. 414), 

 the pistil consists of five verticillate carpels, o, alternating with the 

 stamens, e ; and the same arrangement is seen in Xanthoxylon 

 fraxineum (fig. 414). In the Tulip-tree (fig. 337) the separate car- 

 pels, c c, are numerous, and arranged in a spiral cycle upon an 

 elongated axis or receptacle. In the Raspberry the carpels are on a 

 conical receptacle ; in the Strawberry, on a swollen succulent one ; and 

 'in the Eose (fig. 294 o o), on a hollow one, r r, ct, which is probably 

 a prolongation of the torus. 



Fig. 413. Fig. 414. Fig. 416. 



When the fruit consists of several rows of carpels on a flat 

 receptacle, the innermost have their margins directed to the centre. 



Fig. 413. 1, Summit of the style, t, of Hibiscus palustris, dividing into five branches, 

 which are each terminated by a stigma, s s. 2, One of these branches highly magniHed. 

 3, Portion of the surface of the stigma still more magnified, to show its papillse, which are 

 elongated like hairs. Fig. 414. Pistil of Xanthoxylon fraxineum, consisting of five distinct 

 carpels, supported on a gynophore, g. Each of the ovaries, o, bears a terminal style dilated 

 at its extremity into a stigma, s. The five stigmata remain for a long time adherent by their 

 sides. Fig. 415. 1, Carpels of Butomus umbellatus, consisting of folded leaves arranged 

 in different verticils. 2, Section of the same, showing the alternation of the parts of the 

 flower. Three outer leaves of the perianth, o', alternating with three innej: ones, pi^ three 

 rows of stamens, eo and ei, and the carpels, ce and d. 



