PREFACE. 
Vll 
to the definition of the adjective terms, which are 
either used exclusively in Botany, or which are 
employed in that science in some particular and 
unusual sense. The key to this book, and also to 
the substantive terms explained in Organography, 
will be found in a copious index at the end of the 
volume. 
These topics exhaust the science considered only 
with reference to first principles ; there is, however, 
another which it has been thought advisable to ap- 
pend, on account of its practical value, namely 
Phytography (Book IV.) ; or, an exposition of 
the rules to be observed in describing and naming 
plants. As the great object of descriptions in natural 
history, is to enable every person to recognise a 
known species, after its station has been discovered 
by classification, and also to put those who have not 
had the opportunity of examining a plant themselves 
into possession of all the facts necessary to acquire a 
just notion of its structure and affinities ; it is indis- 
pensable that the principles of making descriptions 
should be clearly understood, both to prevent their 
being too general to answer the intended purpose, 
or more prolix than is really requisite. It is the 
want of a knowledge of these rules that renders the 
short descriptions of the classical writers of antiquity, 
and the longer ones of many a modern traveller, 
equally vague and unintelligible. In this place are 
inserted a few notes upon the formation of an herb- 
arium. 
It has been my wish to bring every subject that I 
have introduced down, as nearly as possible, to the 
state in which it is found at the present day. In 
doing so, I have added so very considerable a quan- 
tity of new matter, especially in what relates to 
