366 On the Genealogy of Plants. [June, 
OLD SYSTEM. 
Polypetalze 
Angiosperms Monopetalze 
Apetale 
Exogens 
netaceze 
Gymnosperms Coniferze 
Phznogams Cycadaceze 
Endogens 
NEW SYSTEM. 
: Monopetalz 
Dicotylee Polypetalze 
(exogenous) Apetalæ 
Angiosperms 
Monocotylæ 
(endogenous) 
Phænogams 
a 
Gnetacez : 
exogenous ‘a 
Gymnosperms / Coniferæ 
Cycadaceæ (endogenous) 
The terms Monoctyle and Dicotyle are preferable to Endo- 
gen and Erogen, for the Angiosperms, since they lead to no 
confusion with the class Gymnospermæ. In this classification 
the terms conform to the strict rules for definition, each being ja 
wholly exclusive of all the rest. The reason for transposing the =<] 
Polypetale and Monopetale will be given in another paper. 4 
Before proceeding to consider more especially the manner in a 
which the Angiosperms may have been derived from the Gymno- 
sperms, it will be necessary to glance once more at the nature of 
_ the cryptogamic vegetation from which we suppose the latter to 
a have descended. And for our purpose we may conveniently 
divide it into three gronpe: Ist, the group of true ferns; 2d, the 
