as extended and minute as appeared to the author necessary for the com- % 
plete recognition of the plants, and for imparting a knowledge of ieuelll 
is peculiar or interesting in their habit, culture, or use. 
With regard to the sources of information from which this part of the 
work has been prepared, it is proper to state, that I have for several years 
been engaged in the collection of materials, during. which I have made 
extensive tours with this object in view, in nearly every section of country 
which this Flora represents, and have had access to numerous and exten- 
sive herbaria. By these means, I have been able to draw the description 
of about nine tenths of the specie¥ mentioned from the living or dried 
specimen. For additional information, I have availed myself of the best 
authorities within my reach, among which are the botanical works of 
Bigelow, Eaton, Wright, Pursh, Michaux, Smith, Nuttall, Torrey, Beck, 
Loudon, Eliott, Darlington, Dewey, Barton, Hooker, Decandolle, and 
Torrey and Gray. 
With few exceptions, I have adopted, ‘for our native and naturalized 
plants, the nomenclature of the “North American Flora” of the two last 
distinguished authors; and for our cultivatéd exotics, the nomenclature of 
the “Prodromus” of Decandolle, (that is, so far as these floras:at present 
extend,) regarding these, as they truly are, standard works. 
The present Flora is accompanied with numerous Analytical Tables, de- 
signed to facilitate the hitherto tedious process of botanical analysis. The 
object aimed at in their construction is to’exhibit at one view the most 
striking characteristics of each group to which they respectively relate,'so 
arranged as to conduct the mind from a single radiating point to any de- 
sired genus contained in the volume. ‘That we have fully realized this 
plan, or that the tables are free from error, is not'to be expected; yet’'we 
do hope that they will afford facilities for analysis greater than any system 
hitherto available. 
To Dr. Epwarp E. Puetps, Lecturer on Medical Botany, &c. in 
Dartmouth College, I am indebted for many highly valuable suggestions, 
particularly in regard to the tables above mentioned. In this department 
of the work, I would gratefully acknowledge his aid. A few tables under 
‘the Natural Orders were originally of his construction, although necessarily 
‘much altered in this edition, by the admission of additional genera. He 
has also granted me free access to his botanical books and spécimens. 
To the Rev. Professor CoestER DrEwry, to whom I am permitted to 
dedicate this volume, I am indebted for that part of the Flora which re- 
lates to the difficult yet deeply interesting family of the Carices. He'has 
not only granted me access to his former excellent monograph of ‘that 
genus, but has prepared the article for the present work with his own 
hand. 
4 PREFACE. 
% P 
