Vi 
bring together, under the name of alliances or classes, groups of allied orders 
which are occasionally widely separated by the procrustion operation of linear 
characters. But though much has, by these and othersimilar attempts been ef- 
fected to improve our arrangements, I still think we are far behind Zoology 
through our not having yet discovered in our Exogenous and Endogenous 
groups, those almost self-evident secondary divisions or circlesso clearly marked 
out by nature in the animal kingdom, and so ably taken advantage of by Zoolo- 
gists, in working out their animal system. 
To discover these, if they actually exist in Nature, appears in the present 
state of the enquiry to be the first and grand desideratum towards the discovery 
of the true Natural System of plants, In the mean time however, our establish- 
ed orders and genera being for the most part pretty nearly natural, aided by the 
convenient practical grouping now in use, serves all the purposes of a more 
strictly correct and philosophical arrangement, leaving us for the time, very inde- 
* pendent of a better, and allowing us to proceed at our own pace, leisurely feeling 
our way, while searching for the long and ardently desired natural one. And it 
is in the hope that some of the readers of this exposition of what is wanted, to- 
wards the construction of the basement of the natural system of plants, may be 
induced to turn. their attention to the subject and perhaps that some one 
luckier than the rest, may stumble on a clue which will lead himself or others to 
the desiderated point and enable him, by the formation of truly natural secondary 
groups or circles, to complete at least the lower tier of the edifice. 
It only now remains for me to offer a few remarks on vegetable organi- 
zation, with reference to its employment in the construction of a Natural System 
of Botany. These must unavoidably be brief and imperfect, and probably, so 
far as they go, little to the point, the ideas of Botanists on this obscure subject 
being far from precise or settled on a firm basis, especially in what relates to the 
comparative value which should be assigned to each part, engaged in the com- 
plex organization of an Exogenous plant. 
The organ principally regarded as the basis of all our attempts to obtain 
a natural arrangement is the Embryo, when present, taken in connexion with 
the plant which springs from it, whether, in short, it is mono—or di—cotyle- 
donous, giving origin to an Endogenous or Exogenous plant or is altogether ab- 
sent as in Acrogens ; plants still further distinguished from those of the two 
higher groups by their Cellular texture and the nearly total absence of vascu- 
lar tissue. 
Dicotyledonous or Exogenous plants have a woody stem, varying in solidity 
with their age from the tender herbaceous annual up to the ithioet i stony hard- 
ness of the iron wood tree: increasing, with some exceptions, in thicknedy: by the 
annual addition to the surface, layer upon layer, of new wood, forming rings or 
