Osyris, Loranthus and Viscum. 195 



to an ovuhim, and that the cellular growths constituting the young albumen 

 and young embryo took place from the ends of the pollen tubes themselves. 



This view, which appeared in the 'Gardener's Chronicle,' No. 12, March 

 1841, p. 182, was not corroborated by subsequent observations, made first on 

 Loranthus globosus, in which two of the greatest obscuring causes occurring in 

 Loranthus bicolor do not exist ; the embryo-sacs in the former being confined 

 to the ovarium, and not appearing to be endowed with independent powers of 

 growth. My present opinion regarding Loranthus, as exemplified by the two 

 species I have endeavoured to illustrate, is, that its ovula are reduced to the 

 simplest possible form which an ovulum can assume with reference to the pre- 

 sent generally received opinions of this organ. They who follow M. Mirbel 

 may imagine a simpler form still ; but I believe that his quintine is the em- 

 bryonary sac, or the fourth envelope of almost, and perhaps all, completely 

 developed ovula. As, however, both M. Schleiden and M. Decaisne appear to 

 consider the reduction as carried on to a minor extent, I shall mention the 

 reasons which have induced me to adopt the opinion above stated. 



Of the grounds on which M. Schleiden has based his opinion, that " the point 

 of the nucleus (of Loranthus) is lengthened so as to assutne the appearance of 

 a style*," I regret I am ignorant, because this botanist has appeared to me, 

 since the publication of his memoir " on the Development of the Organization 

 in Phsenogamous Plants," to be one of the greatest authorities on structural 

 points. 



With M. Decaisne's observations I am acquainted through the ' Comptes 

 Rendus' of the Academy of Sciences of Paris, No. 6, Fevrier 11, 1839, and 

 through a translation of his paper " on the Development of the Reproductive 

 Organs of the Misletoe" in the 'Annals and Magazine of Natural History,' 

 May 1841. 



From not having found any opening in the ovulum, M. Decaisne comes to 

 the conclusion that the ovulum of Fiscum album is a naked nucleus, reduced 

 to its simplest form, — a sac inclosing the embryo. As, however, M. Decaisne 

 states previously a well-known fact, that an inner closed envelope is of general 

 occurrence among ordinary ovula, it is evident, I think, that a simpler form 



* These are, I believe, the words of M. Meyen in one of his Reports on the Progress of Physiological 

 Botany, which I have not now by me. 



VOL. XIX. 2 D 



