PREFACE. 



within the grasp of an individual ; and that of any consider- 

 able section of our territory may furnish full occupation for 

 years. To students of the present volume who may wish to 

 extend the sphere of their inquiries ; I have great pleasure in 

 recommending the Flora of the Middle and Northern sections 

 of the United States, by Dr. Torrey of New- York, now in the 

 course of publication. The accuracy and constancy of pur- 

 suit manifested by this gentleman entitle him to all praise 

 from those who appreciate the amount of perseverance neces- 

 sary to accomplish labours of this sort. 

 Boston, June, 1824. 



