RAFFLESIA AR^'ULDI. 407 



when they again become active and increase in size until 

 they once more completely cover it. 



While the developraentj as I have here described it, of 

 the nucleus and its integument in Bafflesia is going on, 

 another change is at the same time gradually taking place, 

 namely, at first a slight bending, which at last ends in a 

 complete inversion, in the direction of the nucleus and its 

 integument in regard to the placenta, with which, ia this 

 advanced stage, the perforated apex of the latter is nearly 

 or absolutely in contact. 



In this change of direction, the ovulum of Bafflesia 

 resembles that of the far greater part of Phsenogamous 

 plants : the change, however, is effected in a way which is 

 much less common, the curvature in Bafflesia taking place 

 solely in the upper part of the funiculus, the direction of the 

 inverted ovulum being parallel with, but distinct from, the 

 portion below the curvature ; whereas in Phsenogamous 

 plants generally, the curvature is produced in that part of 

 the funiculus which is connate with the testa or outer 

 integument. Por this difference, a reason, perhaps, may 

 be assigned ; the integument which generally forms the 

 testa or outer coat being in Bafflesia entirely wanting, or 

 only indicated by the remarkable dilatation of the apex of 

 the funiculus.' 



In the more essential points of structure, the ovula of 

 Hydnora and Cytinus agree with that of Bafflesia. They 

 differ, however, in both these genera in retaining their 

 original direction. 



In Hydnora I have ascertained the perforation of the single 

 integument and the position of the included nucleus, pa? 

 but the very earliest stages I have not yet distinctly seen ; 

 while in Cytinus, in addition to the coat analogous to that 

 of Bafflesia and Hydnora, a two-lobed or bipartite mem- 

 brane is observable. 



Of these three genera, I have hitherto observed the pollen 



1 The earlier production of the inner of the two coats generally present in the 

 ovula of Phsenogamous plants, and the absence of the outer in this and several 

 other cases, will probably be considered a valid objection to the terminology of 

 M. Mirbel. 



