DIVISION BY ELEMENTARY ORGANS. 123 



Link prefers the terms of Homonemece and Hetero- 

 nemecc, to designate the classes of which I have been 

 speaking; but I persist in preserving those of Cellu- 

 LARES and Vasculares — 1st, Because they are okler ; 

 2d, Because the terms proposed by Link, which signify 

 similar and dissimilar filaments, seem to me likely to 

 originate inaccurate ideas. 



Among Vascular Plants we can also establish two 

 great fundamental divisions, viz : — 



1st. Those which have all their vessels and elongated 

 cellules directed longitudinally, and w^here the new 

 fibres are always developed toward the centre of the 

 trunk. 



2d. Those which have the vessels or bundles of elon- 

 gated cellules directed either longitudinally or trans- 

 versely, and the new fibres of which are developed 

 toward the circumference of the trunk. The former have 

 received the name of Monocotyledons or Endo- 

 RHiZE^ ; and the latter, in contradistinction, those of 

 Dicotyledons or Exorhize.e. 



I shall designate them here, sometimes by the names 

 of Dicotyledons or Monocotyledons, when I com- 

 pare them with reference to their fructification ; at 

 others by those of Exogens or Endogens, when they 

 are considered with regard to their nutrition. 



It results from this rapid and very elementary 

 summary, that the great primary classes of plants are 

 the following : — 



1st. Dicotyledons or Exogens (all Phanerogamia). 



2d. Monocotyledons or Endogens (Fhanero- 

 c/amia). 



3d. Monocotyledons or Endogens (Cryptogamia). 



4th. Cellular ES (all Cryptogamia). 



The name of Vasculares comprehends the three first 

 of these divisions ; that of Cellulares, only the last. 



