_ 
* 
Oe. ae 
_ PREFACE, 5 
It gives me pleasure to be able also to introduce in this connection the 
name of Dr. James W. Ropsins,—a name long ‘since enrolled among 
American botanists. Our Flora has been recently in part reviewed by 
him; and he has communicated to me, in relation to this work, the results 
_of his extensive and accurate observations, as will be seen by the frequent 
recurrence of his name in the following pages. 
Grateful acknowledgments are also due to Dr. JosepH Barratt. He 
has kindly communicated his unequalled monograph of the willows, “ Sali- 
ces Americane ;” also that of the “ Eupatoria verticillata;” both of which, 
abridged, I have adopted in this work. 
Among other friends and correspondents, from whom I have received 
- specimens and highly valuable information, and whose kindness will be 
held by me in most grateful remembrance, are the following: viz. Dr. AL- 
BERT G. SKINNER and Dr. Joun PrumMeEnr, Indiana; Dr. SamueL B. 
Mzeap and Rev. E. JENNEY, Illinois; Mr. Wa. S. SuLttrvant, Professor 
Locks, and Mr. JosrpH Cxiarx, Ohio; Dr. I. A. LaApHAm, Wisconsin ; 
Dr. Wm. DaruineTon, Pennsylvania; President Hircucock, Professor 
Asa Gray, and Dr. Aucustus A. Gouip, Massachusetts; Mr. Tru- 
MAN RickarD, New Hampshire; Dr. SarTwEtu and Mr. BROWNNE, 
_ New York; Mr. S. T. Otney, Rhode Island; &c. &c. 
In the present edition, a chapter on the principles of Agricultural 
Chemistry has been added to the “ Elements,” and some important altera- 
tions introduced. ‘The Flora has been to a great extent rewritten, and 
enlarged, not only by the addition of such plants as were necessary to 
adapt it to a wider section of country, as mentioned above, but by many 
plants recently discovered within our former limits. At the end is appended 
a synoptical view of the lower orders of the Cryptogamia, with their gen- 
era; and the whole is now illustrated with numerous engravings. 
Finally, the present work is again submitted to the public with the assur- 
ance that, on the part of the author, it shall still be his constant care to 
detect and rectify its imperfections in future editions; and with the earnest 
hope that his labors may serve to awaken in the minds of others as deep 
an interest in this branch of the study of Nature as they have done in 
his own. . 
MERIDEN, N. H., Apriz, 1847. 
