372 FOURTH GROUP. SEED-PLANTS. 



Rosiflorae. In both these forms of flowers the gynaeceum is free ; the torus takes no 

 part in the formation of the wall of the ovary, though it appears to do so sometimes in 

 many perigynous flowers, as in Pyrus and Rosa. Lastly the flower is epigynous, 

 when it has a really inferior ovary; this is distinguished from the ovary which 

 is sunk in the torus of the perigynous flower by having its wall formed 

 from the torus itself, which is hollowed out into the shape of a cup or even 

 of a long tube, while the carpels, which form the entire wall of the free 

 superior ovary, spring like the perianth and androecium from the margin of the 

 hollow torus and only close its cavity above, being there prolonged into the style and 

 bearing the stigmas (Fig. 300). Intermediate forms also are not uncommon 

 between the superior ovary of hypogynous and the inferior of epigynous flowers ; 

 for instance, the lower half of the ovary may be formed of the torus and the upper of 

 the coherent carpels ; transitional forms of this kind are found especially among the 

 Saxifragaceae. 



If the gynaeceum of a flower forms only one ovary, one fruit only proceeds from 

 it, and the flower may then be termed monocarpous (Figs. 300, 301) in contra- 

 distinction to polycarpous flowers, in which the gynaeceum forms several distinct 

 ovaries and as many or fewer fruits (Fig. 299). 



The understanding of the different forms of the gynaeceum will be rendered 

 more easy by a separate consideration of the chief forms ; we may distinguish for 

 this purpose * : 



I. Gynaeceum superior ; stamens hypogynous or perigynous. 



A. Ovules springing from the carpels : 



a. Ovary monomerous: 



a. Ovary one in each flower, 



. Ovaries two or more in each flower. 



b. Ovary polymerous : 



y. Ovary unilocular, 

 8. Ovary plurilocular. 



B. Ovules springing from the torus inside the ovary: 



t. Ovules one, terminal, 

 Ovules one or more, lateral. 

 II. Gynaeceum inferior ; stamens epigynous : 



C. Ovules springing from the carpels : 



17. Ovary unilocular, 

 6. Ovary plurilocular. 



D. Ovules springing from the torus inside the ovary : 



i. Ovule single, terminal, 



K. Ovules one or more, lateral. 



1 [The terms monocarpellary z&&foZycarpellary applied to gynaecea formed respectively of one and 

 of more than one carpel and the terms syncarpous and apocarpous indicating the union or non-union of 

 the carpels in a gynaceum are familiar to English-speaking botanists. But as monomerous and poly- 

 merous, monocarpous and polycarpous as used and defined in the text are not quite coextensive with 

 them, it has been found necessary to retain the terminology of the German edition.] 



