PRELIMINARY TREATISE. 
13 
So difficult is it for man to penetrate the mysteries of nature, 
that no science can be cultivated successfully, of which the 
professors are tenacious of the sentiments they have adopted, 
and not willing at all times frankly to reconsider the opinions 
they have advanced, as different facts, or different views of 
facts already ascertained, are presented to their notice. But 
it is scarcely less important to establish some fundamental 
principles by which the mode of forming and arranging the 
inductions to be drawn from the facts which are ascertained, 
may be divested of capricious uncertainty; or the information 
that is obtained will become a mass of confusion, the more 
palpable, from the futility of the attempts to disentangle it. 
The first great division of the vegetable creation is between 
those in which sexual propagation is manifest, and those in 
which, as in funguses, the mode of increase is a concealed 
mystery : they have therefore been called phanerogamous 
and cryptogamous, that is, the first having manifest, the 
second concealed, wedlock ; which seems to me preferable 
to the later terms sexual and sexless, because the latter 
word assumes a fact which cannot be substantiated. The 
next division of phanerogamous plants is into monocotyle- 
donous and dicotyledonous, the latter having two seedling 
leaves, the former one, or rather that which stands in lieu 
of cotyledons; and perhaps acotyledones without any, con- 
sisting of the root-flowering plants like Rafflesia, which are 
little understood. In the former the growth is said to be 
made by successive additions to the outside, in the second, 
to the centre of the plant, whence they are also called 
Exogenous and Endogenous ; the former, at least in their 
perfect formation, being recognised by a distinct deposit 
of bark, wood, and pith. These are the great separations 
of the vegetable creation, and it will not appear that any 
kindred races are found indiscriminately in either division, 
thougli there is a point of approximation between the mono- 
cotyledonous and dicotyledonous plants. These lines are 
therefore clear and substantial; but we cannot proceed a step 
further without danger of error, by placing a less important 
before an essential distinction. The Amaryllidaceie, which I 
have undertaken to arrange, belong to the monocotyledonous 
plants, which, being less numerous, can of course be more 
easily classed. Although I have not sufficient knowledge 
of all the orders they contain, to flatter myself that I can 
make a perfect disposition of them, yet, as it is necessary for 
