ANGIOSPERMS. 



373 



The important point in the superior gynaeceum is that it is essentially a foliar 

 formation, constituted by the carpellary leaves or carpels, which usually also produce the 

 ovules; the ovules as a rule spring from the margins of the carpels, as in Fig. 302, 

 but sometimes also from the whole inner surface, as in Fig. 299 C. The ovary is 

 monomerous when it is formed of one carpel only, the upper or inner surface of 

 which is curved concavely inwards and the margins are applied to each other and 



D 



FIG. 302. Phaseolus vulgaris. A transverse section of the flower-bud; z calyx-tube, c corolla, f filaments of the 

 outer, a anthers of the inner circle of stamens, K the carpel. B longitudinal section of the carpel with the ovules SK and 

 the stigma n. C, D, E transverse section of carpels of different ages ; SK their marginal ovules, g mid- rib of the carpel. 



cohere, so that the mid-rib runs along its back, while the ovules, when they are 

 marginal, are placed opposite to it in two rows ; but the inflexed margins of the 

 carpel may swell up and form thicker placentas, as in Fig. 303, and produce several 

 rows of ovules, while on the other hand the number of ovules is not unfrequently 

 reduced to two, as in Amygdalus. In monocarpous flowers there is only one such 



FIG. 304. Gynaeceum of Pyrola umbellata. A in longitudinal section ; 

 s sepals, / petals, st filaments of the stamens, f ovary, stigma, d nectar- 

 glands. B transverse section through the ovary; ./its wall, pi the pla- 



FIG. 303. Gynaeceum of Saxifraga 

 cordifolia. A in longitudinal section ; 

 g the style, n n the stigmas. B trans- 

 verse sections at different heights ; / the 

 placentas. 



carpellary leaf, as in Figs. 301, 302 ; in polycarpous flowers there may be two, three, 

 or more, or even many; if there are two, three or five they are usually arranged in a 

 whorl; if there are four, six or ten, they are usually in two alternating whorls 

 (Fig. 299 B, I) ; if there are a considerable number of monomerous ovaries in a 



