XiV 
PREFACE. 
The diagnoses which in the first edition were prefixed to the chai’ac- 
ters of the orders, are here struck out ; I have been disappointed in 
their utility, and I do not see how to improve them enough to render 
them much better. 
The analytical table has been entirely reconstructed, and I trust upon 
a better principle. One of the great faults of that prefixed to the first 
edition consisted in no provision being made by it to meet cases of ex- 
ceptional structure. This has now been attended to. 
Finally, I have collected under each natural order all the genera that 
I find referred to it in books ; to these I have added their synonyms ; and 
of the whole a copious index has been prepared. This has been a task 
of no small difficulty, and certainly could not have been executed with 
less assistance than I have received through the kindness of my friends 
and correspondents. When I state that the lists of Labiates and Scro~ 
phulariacecB have been furnished by Mr. Bentham, of Compositce by 
Professor De Candolle, of Algce by Dr. Greville, of Amaryllidacece by 
Mr. Herbert, of Ferns and Mosses by Dr. Hooker, of Lauracece^ 
Acanthacece, Graminacece^ and Hepaticce by Professor Nees v. Esen- 
beck, and finally, of Chamcelauciece by Mr. Schauer, of Breslau, it will 
at once be seen that some of the greatest impediments in the way of 
forming a complete list of genera have been removed for me. Never- 
theless, I am extremely apprehensive lest this part of my work should 
be found more defective than I expect; very defective it must neces- 
sarily be ; and I do hope that Botanists will do me the kindness to 
point out such errors or omissions as they are acquainted with, so that 
in a future edition a greater degree of accuracy may be ensured. 
As the lists of genera in some cases contain names which now appear 
for the first time, I have given the characters of such genera in an ap- 
pendix, referring to them by numbers affixed to the names. 
It was my wish to have added to these introductory remarks .^n 
abridgment of the characters of the classes, sub-classes, groups, alliances, 
and orders, so as to bring their resemblances and differences more closely 
into view. But I find that my matter already exceeds the limits of a work 
Avhich is chiefly intended as a class book ; so that I am constrained 
to refer the reader to the short characters already given in my Key to 
Botany; and to some general observations upon classification, of which 
I contemplate the speedy publication. 
