Imperial Inslilule of France. 46* 



lobes aflhering at the point oF junction oF the two other 

 pans, aFttr having For some time perFormed the part of the 

 leaves, would be soon dried and disappear. 



The small conical tubercle bears among botanists the 

 name oF radicule, the pari opposite which, by developing 

 itselF, gives the-entire trunk oF the plant, is cnWed plumule, 

 and the two lateral lobes are called cotyledons. 



Numerous experiments have shown that the functions ot 

 the cotyledons consist in Furnishing the substance necessary 

 to the first development oF the plumule and the radicule, 

 until the small plant is strong enough to extract From the 

 earth and From the atmosphere the juices adapted For it* 

 ulterior growth. 



Observations not less numerous have shown, that plants 

 with two cotyledons, which are the mo.-,t numerous in 

 nature, have a great number oF common characters, and 

 that they differ mostly in the details of their organization 

 From those which have only a smgle cotyledon, and still 

 more From those where no cotyledons are observable : con- 

 sequently botanists have Formed From this composition of 

 the small vegetable embryo, the basis oF their first division 

 of plants. 



M. Desfontaines, in a memoir cF which we formerly 

 gave an analysis, .seemed to have put a seal upon this divi- 

 sion, by proving that the ligneou-^ trunks oi the dicotyle- 

 donal plants have another Internal texture, and another 

 manner oF grow mg tlian those oF the mono-cotyledones 

 and the acoiylcdonts. 



But as it Frequently happens in natural history, particu- 

 larly v\hen the Fundamental characters rest upon empirical 

 observations only, and the rational relations oF which with 

 the rest oF the organization have not been gradually ap- 

 preciated, these rules are not without exception. It has 

 been discovered tliat in the seeds oF certain plan;s, which 

 throughout their whole structure resemble the dicotyledones, 

 or those which have no cotyledons, or which have more 

 than two, exceptions in an inverse ratio have been supposed 

 to exist, and these notions have excited the attention of 

 botanists more than ever to the exanujiation oF the seeds of 

 all the plants. In the course oF this investigation, however, 

 some were Found, the structure of which appeared proble- 

 matical, and in which the same organ received ditferent 

 names according lo the way in which each was regarded. 



'Ilie iteltimbu is one oF the most remarkable ot these 



douhitui species : it is an Indian plant, winch has a consi- 



tlerable resemblance to our nemiphar : its seed contains a 



VdI.40. Mo. l70.Dec. 1812. Gg body 



