4 PREFACE. 



as extended and minute as appeared to the author necessary for the com- 

 plete recognition of the plants, and for imparting a knowledge of whatever 

 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 arid exten- 

 sive herbaria. By these means, I have been able to draw the description 

 of about nine tenths of the species 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, Elliott, Darlington, Dewey, Barton, Hooker, D.ecandolle, 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 cultivated 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 gjjpup 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. EDWARD E. PIIELPS, 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 specimens. 



To the Rev. Professor CHESTER DEWEY, 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. 



