184 Mr. Griffith on the Ovulum o/'Santalum, 



I have not been able to find any such ovarial cavity in the two species of 

 Viscum I have lately examined ; but my inquiries have not been made at a 

 sufficiently early period, on which Loranthus, I think, shows so much depends. 

 Further observations on Viscum will, I almost feel convinced, show that an 

 obscure ovarial cavity similar to that of Loranthus exists : for in addition to 

 the strong doubts that must arise from any apparent infraction of a general 

 law, M. Schleiden has stated that in Viscum album there is a nucleus, and 

 consequently an ovarial cavity. 



The late appearance of the ovulum does not, I think, present so remarkable 

 an anomaly as the solidity of the ovarium, unless it can be shown that the 

 development of the ovulum results from the action of the pollen. For there 

 are many instances, I think, of considerable irregularity in the degree of de- 

 velopment of the ovulum at the period of expansion of the flower ; and the 

 rather later appearance of the ovula of Loranthus is, it appears to me, in exact 

 accordance with the nature I have ventured to assign to them ; the embryo- 

 nary sac being the last part of the independent ovulum that is formed, not 

 being evident, perhaps occasionally, until the action of the pollen on the 

 stigma has taken place. 



From M. Decaisne's description of the ovulum of Viscum album, which 

 appears to agree tolerably well with that of an Himalayan species it is I 

 think, evident that in the earlier stages of its development it may defy obser 

 vation, smee at one period it would seem to consist of nothing but a sinde 

 cell, scarcely if at all, distinguishable from the cells composing the sur- 

 rounding cellular tissue. 



The apparent determination of the development of the ovulum by fecunda- 

 lon and the lapse of time mentioned by M. Decaisne as intervening between 

 he two processes, appear to me very remarkable. The first would seem to 

 m er the absence of any pa.pab.e pre-existing punctum on which the 1 



apparent y famished with n,a.e organs, have no evident^ 12 



o a p.std.nm , because, if the ma.e influence of Vu mm JL be so exerXd 



as to cause the development of the embryonary sac, fol.owed by that o he 



