ANGIOSPERMS. 



559 



When the axial part of the flower, the Receptacle or Torus, is so elevated in the 

 centre that the base of the gynseceum lies evidently above the stamens, or at least in 

 the middle of the androecium, the perianth and the androecium, or even the 

 whole flower, is said to be hypogynoiis (Fig. 382). When, on the contrary, the 

 receptacle is hollowed out like a cup or saucer, bearing the perianth and stamens on 

 its annular margin, while the gynaeceum springs from the bottom (Fig. 384, A), the 

 flower is said to be perigynous. It is obvious that intermediate forms are possible 

 between extreme cases of hypogynous and perigynous flowers ; and these are in fact 

 common, especially among Rosiflorae. In both these forms of flower the gynasceum 



Fig. 384. —Flower of Eletagnus 

 fitsca : A lonjjitudinal section, d disc ; 

 B diagram. 



Fig. 383.— Longitudinal section through the inferior owary of Eryng-ium catnpestre; I sepals, c petals, y filament, gr style, 

 h disc, KK nucellus of the ovule, i integument. 



is free, the receptacle taking no part in the formation of the wall of the ovary, 

 although this appears to be the case externally in some perigynous flowers, 

 as Pyrus and Rosa. The flower finally is epigynous when it possesses an actually 

 inferior ovary. This latter is distinguished from the ovary which is buried in the 

 receptacle of perigynous flowers by its wall being formed of the receptacle itself 

 hollowed out into the form of a cup or even of a long tube. The carpels, which in 

 the case of the free superior ovary form its whole wall, spring in the inferior ovary 

 (like the perianth and the androecium) from the margin of the hollow receptacle, 

 and only close up the cavity above, where they are prolonged into the style and 



