INTRODUCTION. 



It is the duty of all the observers of natural 

 productions to communicate their discoveries 

 and researches. When a botanist has spent a 

 long life in travelling over both hemispheres, 

 collecting 100,000 botanical specimens, draw- 

 ing 2000 plants, and discovering a multitude of 

 new objects, as I have done : this duty becomes 

 still more imperative. When to these exertions 

 he may have added deep researches in the criti- 

 cal examination of many thousands specimens 

 of plants from all parts of the Earth; and in 

 consulting Books and Libraries, former authors 

 and figures. Gardens and Herbals ... as I have 

 also done, this duty assumes the aspect of ne- 

 cessity ; particularly if what he has ventured to 

 publish heretofore in unconnected works, has 

 not been widely spread nor duly appreciated or 

 quoted, owing to the difficulty of times, circum- 

 stances, shipwrecks, or scattered tracts in re- 

 mote places. 



Such having been my case ; I felt the need of 

 revising and combining all my botanical labors, 

 both published and unpublished, while I was 

 engaged in printing my New Flora of North 

 America, a kind of Mantissa or Supplement to 

 all the previous Floras of that continent by Lin- 

 neus, Clayton, Michaux, Muhlenberg, Pursh, 

 Robin, Nuttal, Torrey, Beck, Bosc, Lamark, 

 Hooker, Elliot, Eaton, Riddell, Bigelow, &c. 

 Besides the numerous plants unnoticed by them, 

 I found so many Species and Genera blended 

 or in disorder, that it required a very extensive 

 critical survey of those connected thereto else- 

 where, to compare and ascertain the truth. 



