Osyris, Loranthus and Viscum. 183 



dation, or rather, after the action of the pollen upon the stigmatic sur- 

 faces, 



2. The reduction of an ovulum to the nucleus or to the embryonary sac. 



3. The embryonary sac. 



4. The origin of the embryo. 



1 . Solidity of the Ovarium, 8^c. 



The only evidence in favour of the occurrence of a solid ovarium that re- 

 mains uncontradicted is, so far as I know, that of M. Decaisne on Viscum 

 album, and that derivable from some casual observations made by myself 

 early in 1 838 on a Himalayan species of the same genus ; and the evidences 

 in favour of the occasional appearance of the ovulum after the first parts of 

 the process of fecundation have been accomplished, are drawn solely from my 

 observations on the Mergui Viscum, and those of M. Decaisne on the European 

 plant. For having erroneously stated the existence of so remarkable an ano- 

 maly in Loranthus, I cannot hope to escape censure on the grounds of the 

 obscurity of the appearances ; these, on the contrary, ought to have made me 

 more than ordinarily careful in the manner and amount of investigation : for 

 there is, perhaps, nothing more constant than the existence of a cavity in the 

 pistillum, nor is its absence compatible throughout with the very general, and 

 perhaps universal rule, regarding the composition of a pistillum from one or 

 more involute carpellary leaves. 



It is easy to conceive a pistillum without any very manifest cavity ; for the 

 space, which must exist from the disposition of its component parts, may be 

 filled by an extension of the placentee, or the margins of the laminae of those 

 component parts, and indeed by several other modes of extension of its inner 

 surface. But the solidity which I so prematurely announced as existing in 

 Loranthus was of a very different nature, and could not be reconciled to the 

 idea of a pistillum, which I have been led to adopt. The anomalies of the mere 

 pistillum of Loranthus I at present consider to be confined to the obscurity of 

 the cavity, particularly as connected with obscurity of the placentae. I have, 

 however, seen in Loranthus bicolor appearances which lead me to suspect that 

 much still remains to be observed, not only as regards the conical eminence 

 from the fundus of the cavity, but as regards the true limits of the ovarium. 



