•ilO ON THE FEMALE FLOWER AND FRUIT OF 



found, consisting entirely of a more minute and much less 

 dense cellular tissue. On the surface of this embryo I have 

 observed no point marking original attachment, nor any 

 239] indication of a channel connecting it with the surface of 

 the albumen, in the centre of which it is seated. 



In Cytiniis, in which I believe I have at length foand 

 ripe fruits, the seeds are extremely minute, and generally 

 retain at their base the bipartite membrane more distinctly 

 observable in the unimpregnated ovulum. To this mem- 

 brane the name of arillus may be given ; but it may also, 

 and, perhaps, with greater probability, be considered the 

 imperfect production of the testa or outer membrane. 



The seed itself is elliptical, with a slight inequality at 

 top indicating the depression or perforation observable in 

 the ovulum. The single integument of the seed is easily 

 separable from the nucleus, and by moderate pressure splits 

 longitudinally and with great regularity into two equal 

 portions ; in texture it is a crustaceous membrane, indis- 

 tinctly reticulate, the areolss, when very highly mag- 

 nified, appearing to be minutely dotted with a semi-opaque 

 centre. 



The nucleus, corresponding exactly in size and form 

 with the integument, has its surface also reticulate, but the 

 areolae are not dotted ; and it appears, as far as I can as- 

 certain in so minute a body, to consist of a uniform cellular 

 tissue, very exactly resembling the nucleus of an Orchideous 

 plant. 



The result of the comparison now made, and which 

 might be extended to other points of structure of Rafflesia, 

 Brugmansia, Hydnora and Cytinns, seems to be, that these 

 four genera, notwithstanding several important diiferences, 

 form a natural family to which the name of Rafflesiace^ 

 may be given ; and that this family is again divisible into 

 three tribes or sections : 



The first Bajlesiece, consisting of Rafflesia and Brugman- 

 sia, is distinguishable by the ovarium being either in part or 

 wholly superior to the origin of the calyx, in its composition 

 or internal structure, in the placentation and direction of 



