ANGIOSPERMS. 



561 



or more, or even a very large number : if the number is two, three, or five, they 

 usually stand in a whorl ; if four, six, or ten, they are generally arranged in two 

 alternating whorls (see Fig. 382, B, I). When the number of monocarpellary 

 ovaries in a flower is considerable, as in Ranunculacese, Magnolia^ &c., the part 

 of the axis which bears them is commonly elongated (to a very considerable ex- 

 tent for example in Myosurus), and their arrangement is then spiral. The mono- 

 carpellary ovary is originally always unilocular, though it may subsequently 

 become multilocular from the production of ridges by the luxuriant growth of 

 the inside of the carpel, which divide the cavity longitudinally into compartments, 

 as in Astragalus, or transversely, as in Cassia fistula. Ovaries of this kind may be 

 distinguished as monocarpellary with spurious loculi, but ought not to be called 

 polycarpellary. 



A polycarpellary (compound) ovary is always the result of the union of all the 

 carpels of a flower, the number being usually two, three, four, or five, arranged 

 in one whorl, the floral axis terminating in the midst of them. If the separate 



FIG. Tfic^.—Phaseohcsvuloaris; A horuontal section through the flower-bud, /calyx-tube, ccoroUa.y filaments of the outer, 

 a anthers of the inner staminal whorl, K carpel ; B longitudinal section of the carpel, with the ovules SK and stigma n ; C, D, E 

 horizontal sections of carpels of different ages, -^A'the parietal (marginal) ovules, g; mid-rib of the carpel. 



carpels remain open, and cohere in such a manner that the right margin of one 

 unites with the left margin of another, the result is a unilocular polycarpellary 

 ovary. The placentation is in this case parietal when the coherent margins project 

 only slightly inwards, as in Reseda, Viola, &c. But if the coherent margins of the 

 carpels project further inwards, the cavity of the ovary becomes imperfectly multi- 

 locular, the chambers being connected with one another in the centre, as in Papaver, 

 where the imperfect dissepiments are covered on both sides by a number of ovules. 

 A bi- or multilocular polycarpellary ovary results when the margins of the carpels 

 project inwardly so far that they meet or cohere either at or near the axis of 

 the ovary, the elongation of the floral axis in the centre frequently contributing 

 to this result. The mode of cohesion of the carpels in multilocular ovaries may 

 vary greatly in other respects, according as it takes place along the whole length 

 of their inflexed margins, or only below, while the upper parts resemble 

 a whorl of monocarpellary ovaries (Figs. 386-389). Since the margins of the 

 carpels which meet in the centre become developed into the placentse, the ovules 

 make their appearance in the central angles of the loculi (axile placentation), as 



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