and on various Plants related to them. 309 



in the one it is developed from an ordinary ovalum ; in the other from ft lac 

 or body, of whieh the analogy is by no means so evident And it is to this 

 that the sedulous attention of observers should be directed; for in the first 

 type we may expect to find the same mode of fecundation, and germination 

 from a definite and producible point. In the other, in the absence „f know- 

 ledge of the early nature and attachments of the sac. all at present must be 

 conjecture: the only analogy we can found thereon is the analogy of the pro- 

 tecting organ, with an ordinary phamogamous pistillum; and even this mav 

 be considered as beginning to fail in Balanophora. 



There is another point of view in which the absence of an ordinary form ,,i 

 embryo maybe considered, and which is suggested by the resemblance the 

 bod}', which I take to be embryo, has to some forms of albumen. It il easily. 

 I think, conceivable that the existence of a particular form of embryo may be 

 beyond the means of investigation not founded on the study of germination. 

 For if there are all sorts of degrees of development of the vegetable embryo, 

 of which Tacca and Houttuynia maybe taken, perhaps, as the greatest ex- 

 tremes known in one direction, it is not altogether unreasonable to imagine 

 the occurrence of a greater amount of reduction. And although so minute a 

 form might not escape a practised observer occupied by a full series of speci- 

 mens, it may easily escape one occupied by the ripe seed alone, and this for 

 the most part derived from dried specimens. 



It is also known, that the detection of the very first appearances of the 

 embryo of ordinary Phsenogamous plants demands higher appliances than 

 have been hitherto bestowed on the study of Rhizanths generally. And it is 

 I think to be expected that cases may occur in which the development of the 

 embryo ceases at a point corresponding to its earliest degrees of development 

 in ordinary instances. Granting such, its observation may easily be obscured 

 in casual examinations. 



Obs. IF. — There are also theoretical arguments which, I venture to think, 

 may be made to bear upon this question. 



Against the arrangement of these plants into one group it may be urged, 

 that the principles of variation, by which almost all the peculiarities of the 

 three subkingdoms are mutually represented, are nowhere so limited ; but. on 

 the contrary, occur among plants possessed, so far as we can judge, of very 

 different organizations. Thus the venation characteristic of DkotyleAm 



