THE ANGIOSPERMAE 



1137 



the placentae, even in superior ovaries, now seems to us, in the hght of 

 fossil evidence, quite outmoded, nor are we inclined to allow to the torus 

 or disc, as a term applied to the receptacle lying between calyx and gynoe- 

 cium, the status of a distinct and peculiar organ of the flower. We have 

 not sufficient information to judge how frequent any one morphological 

 condition may be among Angiosperms, nor, except in certain cases, what 

 the condition is in individual species, but it is reasonably certain that there 

 are various possibilities* and that no one condition is universal. Including 

 the conditions already mentioned, the following relationships are all 

 theoretically possible as explanations of the inferior position of the ovary. 

 They have been thus summarized by Douglas (Fig. iiii). 



Fig. 1 1 1 1. — Diagrams illustrating types of inferior o\aries with vary- 

 ing amounts of axial (shaded) and appendicular (unshaded) tis- 

 sues, according to different constructional theories. A, Ovarj' 

 wholly appendicular. B, Placenta axial. C, Ovary axial except 

 for carpellary lid. D, Cup axial, ovary appendicular. E, Cup and 

 placenta axial, ovary appendicular. F, Cup axial, placenta appen- 

 dicular. (After Douglas.) 



1. The outer floral whorls are concrescent around the ovary, to which 

 they are adnate. This was the theory advanced, though obscurely, by A. P. 

 de Candolle in 1827, later clearly advocated by Van Tieghem and recently 

 supported by Eames as applicable to the majority of species. (Fig. mi, 

 A and B.) 



2. The whole of the inferior ovary consists of receptacular tissue, bear- 

 ing ovules, the carpellary wall being reduced to a sterile covering including 

 little more than the styles and stigmas. This theory originated with Schlei- 

 den in 1839 and was held by most of the German school of botanists in 

 the nineteenth century. (Fig. mi, C.) 



3. The inferior ovary consists of a concave receptacle enclosing true 



