228 



COMPENDIUM OF GENERAL BOTANY. 



ovules are, as a rule, situated along the margins (placentce) of the 

 carpellary leaves or leaf. The number of carpellary leaves produces 

 either a monomerous or & polymerous gynoecium. The polymerous. 

 gynoecium may either develop into a single ovary, when it is known 

 as a syncarpous gynoecium ; or each individual carpel may develop 

 a pistil, the polycarpous or apocarpous gynoecium (Ranunculaeece). 

 Fig. 156 represents a cross-section of the polymerous syncarpous 



FIG. 1 56. Cross- 

 section through 

 the ovary of 

 Paris quadrifo- 

 lia. 



(After Krass and Lan- 

 dois.) 



FIG. 157. Ovary of Atropa 

 Belladonna. 



A. Longitudinal section ; B, cross- 

 section. (After Krass and Lan- 

 dois.) 



FIG. 158. Central 

 placenta of Pri- 

 mula qfficinalis, 

 with the ovules 

 removed. 



(After Berthold and 

 Landois.) 



gynoecium of Paris quadrifolia / it is usually known as a " four- 

 chambered ovary." Fig. 157 shows the polymerous syncarpous. 

 (two-chambered) gynoecium of Atropa Belladonna. 



The manner in which the carpellary leaf-margins are united 

 sometimes brings the margins nearly to the middle of the cavity of 

 the ovary. This produces what is known as axillary placentation- 

 (Figs. 156 and 157), which is very common. More rarely the 

 margins project little or not at all into the cavity of the ovary, 

 when it is known as parietl placentation ( Violacece). There are 

 also intermediate forms of placentation which produce the incom- 

 pletely many-chambered ovaries (Papaver). The so-called central 

 placentation (for example, of the Primulacece; see Fig. 158) is not 

 well understood from a morphological standpoint. It seems as 

 though the floral axis (torus) produced the ovules. It is, however, 

 possible that a caulome may develop ovaries. 1 



The Position and Form of Ovaries. An ovule is said to 

 be atropous (orthotropous) or straight when it forms a direct con- 

 tinuation with its stalklet or funiculus. The ovule is said to be 

 anatropous when the funiculus extends along and is adherent to the 



1 For fear that this statement may be misleading I will state that a caulonie, 

 as sucJi, will never produce ovaries. TRANS. 



