THE PISTILS. 287 



the style. This is not a mechanical protrusion, but a true growth, 

 the materials for which are supplied by nourishment imbibed from 

 the stigma and style. Its further course and the office it subserves 

 will he considered after the structure of the pistil is made known. 

 (Sect. IX.) 



Sect. VII. The Pistils. 



537. The Pistils (419) occupy the centre of the flower, and ter- 

 minate the axis of growtli. Linna3us established the orders of his 

 Artificial System mainly upon the pistils, and this introduced a se- 

 ries of terms expressive of their number in a flower, analogous to 

 those used for the number of stamens (517). Thus a flower with a 

 single pistil is said to be monogynous ; with two, digynous ; with three, 

 trigynous ; with four, tetragynous ; with five, pentagynous ; and so 

 on : when more numerous or indefinite, the flower is polygynous. 



538. It is comparatively seldom that the pistils are exactly equal 

 to the petals or sepals in number ; they are sometimes more numer- 

 ous, and arranged in several rows upon the enlarged or prolonged 

 receptacle, as in the Magnolia, the Strawberry, &c., and perhaps 

 more frequently they are reduced to less than the symmetrical num- 

 ber, or to a single one. Yet often what appears to be a single pistil 

 is not so in reality, but a compound organ, formed by the union of 

 two, three, or a greater number of simple pistils ; these organs being 

 subject to coalescence in the same way as the stamens (518) and the 

 petals (507, 462). 



539. A simple and complete pistil, as already described (420), is 

 composed of three parts : the Ovaky, or seed-bearing portion ; the 

 Style, or tapering portion, into which the apex of the ovary is pro- 

 longed ; and the Stigma, usually situated at the summit of the style, 

 consisting of a part, or sometimes a mere point, of the latter, divested 

 of epidermis, with its moist cellular tissue exposed to the air. The 

 ovary, which contains tiie ovules, or bodies which are to become 

 seeds, is of course a necessary part of' the pistil ; the stigma, which 

 receives from the anthers the pollen (531) by which the ovules are 

 fertilized, is no less necessary ; but the intervening style is no more 

 essential to the pistil than the filament is to the stamen, and is there- 

 fore not uncommonly wanting. In the latter case, the stigma is 

 sessile upon the apex of the ovary. In Tasmannia it actually occu- 

 pies the side of the ovary for nearly its whole length, and is sepa- 



