PEEFACE. 



The contents of this essay is the result of thirty-five years obser- 

 vations on the vegetation of a small area of about three hundred 

 English square miles. It is intended to show how local floras should 

 be treated to be useful to phytogeography ; how notice should be tak- 

 en of soil and climate, to understand the vegetation of a certain floral 

 district. Descriptions of genera and species are unnecessary, in such 

 treatise, as those can be found in Gray^s Manual, which, being in every 

 botanists hand, offers sufiicient means to identify all the species found 

 in our country. 



May this little book take the initiative to similar treatises, that 

 would in a great measure, facilitate the work of a future writer on 

 phytogeography of North America. 



