184 Mr. Griffith on the Ovulum of Santalum, 



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

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

 sufficiently early period, on which Lorantlms, 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, since at one period it would seem to consist of nothing but a single 

 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- 

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

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

 infer the absence of any palpable pre-existing punctum on which the male 

 influence is to be exercised. And if the development of the ovulum be really 

 found to be the effect of the action of the pollen, it appears to me that con- 

 siderable light will be thrown on those Acotyledonous plants, which, though 

 apparently furnished with male organs, have no evident apparatus analogous 

 to a pistillum ; because, if the male influence of Viscum album be so exercised 

 as to cause the development of the embryonary sac, followed by that of the 



