and on the Structure of Hydnora africana. 225 



Another point, which in my former paper I considered doubtful, namely 

 the seat or limit of the stigmata, is not even now satisfactorily established; 

 for the slender processes forming the hispid tips of the supposed styles, which 

 have so much the appearance of the ultimate divisions of stigma, are merely 

 hairs of a very simple structure, and exactly resembling those found in other 

 parts of the column ; though in several of the specimens examined they were 

 greatly altered in appearance, from a coating of mucous matter taken up and 

 again deposited by the spirit in which the specimens were preserved*. A 

 slight difference, indeed, seems to exist between the tissue of the apices of the 

 styles and the other parts of their surface ; hardly sufficient, however, to prove 

 it to be stigma, though this is no doubt the probable seat of that organ. 



The next point of importance in the female flower of Rafflesia is the struc- 

 ture and gradual development of the ovula. These, in the earliest state ob- 

 served, consist of merely conical or subcylindrical papillae, having a perfectly 

 smooth surface as well as uniform internal substance. 



The first perceptible change taking place in the papilla is a slight contrac- 

 tion at its summit, the upper minute contracted apex being the rudiment of 

 the nucleus. Immediately below this contracted portion a dilatation is soon 

 observable, which, gradually enlarging and becoming slightly hollowed, forms 

 a cup in which the nucleus, also proportionally increased in size, is partly 

 immersed. This cup, the rudiment of the future integument, continues gra- 

 dually to enlarge, until it completely covers and extends considerably beyond 

 the nucleus, but without cohering with it. If a transverse section is made near 

 the slightly-depressed apex of this integument, an extremely minute perfora- 



known species of the genus. But if the placentation oi Rafflesia Arnoldi and Cumingii, notwithstanding 

 the objections stated in the text (p. 223), be considered parietal, as Blume has described it in R. Patma, 

 and as from his figures it seems actually to be in Brugmansia, there would still be no means of deter- 

 mining the exact degree of composition of ovarium in Rafflesia ; for in no species of the genus is there 

 the slightest indication afforded by the arrangement of cavities or ramification of the assumed placentae, 

 to mark any definite number of component parts. Similar objections apply with equal force to the 

 adoption of that opinion which regards placentation as in all cases central or derived from the axis. . 



In conclusion, therefore, it may perhaps be said that Rafflesia, in the structure both of ovarium and 

 antherae, is not obviously reconcileable to any hypothesis hitherto proposed to account either for the 

 origin or for a common type of the sexual organs of Phaenogamous plants. 



* See Mr. Bauer's representation of the hairs in this state, Tab. XXIII. figs. 3, 4, 5, 6 & 7. 



