THE FLOWER. 



margins of the carpellary leaf. In many species of Gentian, as 



:ilso in Obolaria and Bartonia. of tin- same 

 family, the whole internal face of a dic'ii- 

 pellary ovary is thickly ovulifermis. 



.")!):;. Perhaps lln- parietal placenta- in 

 Parnassia (Fig. 552) are borne <>n the 

 midribs of the carpels, for they are directly 

 under the stigmas, instead of alternate 

 with them, as they normally should be. The same thing occurs 

 in Poppies and many other Papaveraceae, also in some Cruci ferae ; 

 and in some of the cases each stigma 

 is more or less two-lobed. This sug- 

 gests the explanation, 1 here probably 

 the true one. which supposes that the 

 placentae are borne on the leaf-margins 

 in the normal way, but that each 

 stigma is two-parted (as if the carpel- 

 lary leaf were deepby notched at the 

 apex, and so its two stigmatic leaf- 

 margins separate, as Drosera illus- 

 trates. Fig. 5.">;!). and th:,t the two 

 half-stigmas of adjacent carpels have 

 coalesced into one body, which would 

 of course stand over the parietal placenta- beneath. Each stigma 

 in such a case, as well as each parietal placenta, would consist 

 of the united margins of two adjacent carpels. 



553 



2. IN GYMNOSPERMS. 



504. GYMNOSPERMOUS (that is, naked-seeded) plants are so 

 named because the ovules, or bodies which are to become seeds, 

 are fertilized by direct application of the pollen, which reaches 

 and acts upon the nucleus of the ovule itself, not through the 

 mediation of stigma and style. In the structure of their (lowers. 

 these plants are of a low or simplified type, in some respect > nol 

 obviously homologous with the Angiosperms which now consti- 

 tute the immense majority of pha-noganious plants. But, up to 

 a comparatively late geological period. ( iymnosperms appeal' to 

 have been the only flower-bearing plants. They are represented 



1 Given by Brown, in tin- I'liinta- Javanica> Kariorcs, above ri'JVrml to. 



FIG. 551. Transverse seet ion of ;ui ovary of Nyruphiea odorata, the carpels ovulifer- 

 OUS over the whole interior surface. 



FIG. 552. Pistil of I':n nassi.-i. with ovary transversely divided. 



FIG. 553. Pistil of l>n>sera liliformis, with ovary transversely divided. 



