138 



ELEMENTS OF STRUCTURAL BOTANY. 



than at its margin, and as the gynoecium occupies this 

 central part, its position is above that of the other floral 

 leaves, as shown in Fig. 1 89. Here the pistil is superior, 

 and the stamens and petals hypogynous. But frequently 

 the outer part of the receptacle grows more vigorously 

 than the centre, forming, in fact, a cup with the pistil 

 in the bottom of it, and the stamens and petals around 



K 



Fig. 189. Fig. 190. Fig. 191. 



its margin (Fig. 190). In this case the pistil may be 

 described as half -inferior, and the stamens and petals as 

 perigynous. Often the cup-shaped receptacle grows fast 

 to the ovary all round. In other cases, the carpels, 

 instead of being developed from the bottom of the cup, 

 spring from the margin, thus forming a roof-like disk, 

 around the edge of which the stamens are attached 

 (Fig. 191). Here the stamens are epigynous, and the 

 ovary is truly inferior. Other cases of epigyny and 

 perigyny arise from the adnation (growing together) of 

 the floral whorls without exceptional development of the 



Figs. 189, 190, 191. Diagrams illustrating hypogynous (H), perigynous (P), 

 and epigynous (E) flowers ; a, axis ; fr, calyx ; c, corolla ; s, stamens ; / 

 carpels ; , stigma ; sk, ovule. (Prantl.^ 



