ESSENTIAL OEGANS — STAMENS. 



213 



veraXov, a leaf), and the insertion of both is looked upon as similar, 

 so that they, are stUl hypogynous, provided they are independent 

 of the calyx and the pistil. In fig. 338, the stamens, e, and the petals, 

 p, are below the pistil or ovary, o, and both are separate from it and 

 from the calyx, c, and are therefore hypogynous. When the stamens are 

 inserted on the calyx, that is, are united to it to a greater or less height 

 above the base of the pistil, then they become lateral as it were in 

 regard to the latter, and are perigynous {■Tregi, around). This is shown 

 in the ilower of the almond (fig. 339), in which the petals, p, and 

 the stamens, e, are united to the calyx, c, while the pistil is free. 



Fig. 337. 



Fig. 339. 



When the union of the parts of the flower is such that the stamens 

 are inserted on the top of the ovary, they are epigynous (M, upon or 

 above). In this case the torus is supposed to be united to the ovary, 

 while the calyx is above it, and bears the stamens. In the Orchis 

 tribe, where the stamens and pistil are united so as to form a column, 

 the flowers are said to be gynandrous. In Aralia spinosa (fig. 340), aU 

 the whorls, calyx, c, petals, p, and stamens, e, are united by the torus 

 to the pistil, and the two latter whorls appear to rise from the point 

 where the calyx joins the upper part of the pistil. These arrange- 

 ments of parts have given rise to, certain divisions in classification. 



Fig. 337. Central part of the flower of Liriodendron tulipifera, fixe tulip-tree, composed 

 of carpels, c c, ■vrhich together form the pistil. They cover the upper part of the axis, a, and 

 below them are inserted numerous stamens, some of which are seen, e e. These stamens 

 are hypogynous and extrorse. Fig. 338. Section of a flower of Geranium Rohertianum. 

 c c, Calyx, p, Petals, e. Stamens. Pistil composed of ovary, o, and style and stigmata, s. 

 t, Torus or Thalamus. The petals and stamens are hypogynous, and the latter are monadel- 

 phous. Fig. 389. Section of the flower of the Almond-tree. The letters indicate the same 

 parts as in the last figure. The petals and stamens are perigynous. The pistn is free. 



