6 INTRODUCTION. 



Here, the new species of this continent shall 

 be chiefly attended to. They are often in as 

 great a disorder as the Genera; many are occa- 

 sionally blended into one, or improperly deter- 

 mined and settled. To give their synonymy is 

 not always an easy task, nor are the varieties to 

 be overlooked. Many botanists mistake real 

 botanical species for varieties or viceversa. In 

 fact all species might have been varieties once, 

 and many varieties are gradually becoming spe- 

 cies by assuming constant and peculiar charac- 

 ters. This is an interesting feature of botanical 

 philosophy, which I shall properly explain and 

 prove hereafter. 



This new Flora is very far, therefore, from 

 being a compilation of former labors : it is quite 

 an original work, chiefly based upon my indivi- 

 dual researches and discoveries, during 36 years 

 of botanical travels and exertions, whereof 24 

 were spent in North America, the main field of 

 my scientific rambles and labors. 



It may perhaps be useful to give here an out- 

 line of my botanical travels in North America, 

 whereby it will be perceived that I have survey- 

 ed and examined more States and regions than 

 any other Botanist perhaps except Nuttall. 

 Thus I was enabled to detect a great number of 

 New Species, and examine many plants alive in 

 Full bloom in their native wilds. It would be 

 well if botanical writers would thus detail us their 

 actual excursions and explorations. 



Some plants are quite local or have very nar- 

 row limits of growth, others are only in bloom 

 for a few hours or days. Many early vernal 

 plants of the Genera Dodccatheon, Clintonia, 

 VernasoltS) Viola, Peltandra, Cypripedium^ 

 &c. can only be seen in narrow localities during 



