206 Dr. Smith's Inquiry into the Structure of Seeds. 



other the nurse, or, if we may say so, the foster brother of the 

 young ascending plant, which last originates from the extremity 

 of the embryo opposite to the root, but always, like that, most 

 intimately connected with the Cotyledons. These indeed, sooner 

 or later, wither away ; when the acquisition of real and more 

 ample foliage renders them superfluous, or no longer necessary. 

 But all Cotyledons do not ascend out of the earth, nor assume 

 any of those functions of leaves in which light is concerned. In 

 the Horse Chesnut, the Cyamus Nelumbo, the Tropceolum majus, 

 and some other plants, they always remain buried, no doubt 

 acted upon by the air or gas alone. Even in plants of the same 

 natural order, Papilionacece, some, as Lupinus, raise their Co- 

 tyledons into the air and light, in the form of very conspicuous 

 green seed-leaves ; while others, as Lathyrus, retain them under 

 ground, concealed in the black skin of the seed, quite out of 

 the reach of every ray of the latter. In these we know a fari- 

 naceous Albumen is lodged, whether they rise into the light or 

 not; and the closest analogy leads us to conclude that their 

 functions are otherwise similar, which can only be with respect 

 to air. Even Cotyledons however are not indispensably requisite 

 to a seed, though the Albumen appears to be, in some form or 

 other, necessary to all seeds. Not to mention the tribes of ve- 

 getables allowed or guessed to be without Cotyledons, and 

 thence, for systematical convenience, denominated acotyledo- 

 nous; all, who have sufficiently considered the matter, know 

 that in those called monocotyledonous, what is vulgarly taken 

 for the Cotyledon is really an Albumen, a part fundamentally 

 distinct in functions from what is proper to a Cotyledon. Thus 

 even so conspicuous a family of plants as the Orchidece, which 

 the faithful Jussieu confesses were only presumed from analogy 

 to be monocotyledonous, or, as he guardedly expresses it, to 



- . have 



