and on various Plants related to them. 313 



place between Monocotyledones and Acotyledones, and in neglect of the struc- 

 ture of Raffleslacece, and perhaps of some others. Lastly, he has separated 

 two classes not marked by any sufficient absolute particularity of form or of 

 structure ; while he has allowed to remain undisturbed the third great sub- 

 kingdom, in which several peculiar natural types exist, and in which, if there 

 be any truth in the MacLeayian zoological system^ they are to be found. 



Obs. IV. — The line of argument I have endeavoured to follow has been 

 drawn with especial reference to three points. 



In the first, I have endeavoured to extend the objections urged by Mr. 

 Robert Brown, founded on the presence of a vascular system, and the absence 

 of any abstract peculiarity in the embryos of these plants. I have also at- 

 tempted to show that these plants are not similar in their parasitism ; and 

 that, even in the moiety I have examined, there would appear to be two re- 

 markably different types of development of the embryo. 



Secondly, I have alluded to the opposition presented, it seems to me, by 

 such a group as Rhizanthece to the system of nature, a chief part of the plan of 

 which seems to me to consist in an extensive interchange of characters, either 

 positively by structure, or negatively by imitation of structure. 



Thirdly, I have adverted to a want of uniformity in opinion of the founders 

 regarding its rank or value, incompatible, it appears to me, with any group of 

 the system of nature. 



And in conclusion I beg to add, that my impression is that Rhizanthece form 

 an entirely artificial group, not even sanctioned by practical facility, which is 

 the only merit of an artificial association : and that its adoption is a retro- 

 grade step in the course of philosophical botany, and in direct opposition to 

 those rules on which the standard divisions and families of the vegetable 

 kingdom have been hitherto based, and I think in most cases not unsuccess- 

 fully. " Vera autem scientia ex prcemissis integrce organisationis studio dedita, 

 nan hceret in pauciorum signorum delibatione, sed omnes omnium organorum 

 modos tenetur perpendere, prcepositd eorum structurce et actionis accuratd expo- 

 sitioneT Jussieii. 



"Nulla hie valet regula a priori, nee una nee altera pars fructificationis, sed 

 solum simplex symmetria omnium partium." Linnaeus. 



2 T 2 



