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parasite, in different stages of development, penetrating the cortical 

 layers of a branch (not root) of a vine.* That they proceed from the 

 interior of the branch, is evident from the place of the yonngest bud 

 being merely indicated by a slight swelling, without any rupture of 

 the bark. In the third stage the parasitical bud has burst the outer 

 cortical layer of the branch, and appears entirely inclosed in a reticu- 

 lated covering : while in the fourth the reticulated covering itself has 

 burst, and discloses the external floral envelopes of the parasite. In 

 reference to this reticulated envelope, Dr. Brown makes the remark 

 in a foot-note, " That the whole of this covering belongs to the stock, 

 is proved by its containing those raphides or acicular crystals which 

 are so abundant in the root of the Vitis or Cissus, and which are al- 

 together wanting in the parasite." This will be hereafter referred to. 



It is with considerable diffidence that I am induced to express, 

 however imperfectly, my reasons for looking upon these curious 

 plants as forming a distinct class, especially as in so doing I am pre- 

 suming to set up my own views in opposition to those of such able 

 botanists as Dr. Brown and Mr. Griffith, who have both possessed 

 greater advantages in studying the plants themselves, than I can ever 

 hope to enjoy. I can, however, truly affirm that I have not jumped 

 hastily at my conclusions, and in forming them I have been mainly 

 assisted by the evidence furnished in the published labours of the 

 above-named gentlemen. I am also happy to find that my views as 

 to the distinctness of rhizogens as a class agree with the opinion of 

 Dr. Lindley, who, in his last great work, ' the Vegetable Kingdom,' 

 in raising them to that rank, appears to have done so on! purely 

 philosophical principles, and I think defends this step in such a way 

 as to meet Mr. Griffith's most serious objections. 



" The first office," says Dr. Lindley, " which all organized beings 

 have to perform is that of feeding ; for it is thus only that their exis- 

 tence is maintained. The second is that of propagating, by means of 

 which their species is perpetuated. These being functions of the 

 highest importance, it is reasonable to conclude that the organs pro- 

 vided for their proper execution must be of the highest importance 

 also, and hence they are beyond all others valuable for the purposes 

 of classification. And, again, because the power of feeding must 

 come before that of propagating, it might be conjectured beforehand 

 that the organs destined for the former operation would afford the 

 first elements of a natural method. But since the action of feeding is 



* This has been determined by Mr. Jack to be the Cissus angustifolia of Roxburgh. 



