PEfiPACE. 15 



range, the southern limits are mentioned ; as Anemone Penmylvan- 

 ica, "W. New England to Illinois and northwestward." And so 

 of "Western plants ; e. g. Isopyrum biternatum, p. 44, « Ohio to 

 Illinois, Kentucky, and westward"; Amorpha canescens, p. 130, 

 « Michigan to Wisconsin and sbuthwestward." But this rule has not 

 always been closely adhered to. 2. Wh^re no habitat or range is 

 mentioned, the species is supposed to be diffused over our whole 

 area; or nearly so, and usually beyond it. 3. When the species is 

 quite local or rare, the special habitat is given ; 6. g. Vesiearia 

 Shorlii, p. 73, and Alyisium Lescurii, p. 72 ; Sullivaniia Ohionis, 

 p. 169, &c. Except in such cases, or when the known geographical 

 range of a species has been recently extended, the want of space has 

 generally demanded the omission of particular stations, which are so 

 appropriately given in local Floras and in more detailed works, but 

 for which there is no room in a maitiial like this. 



For the same reason, I could not here undertake to specify the 

 range of those species- which extend beyond the geographical Kmits 

 of this work, or beyond the United States. Nevertheless, to facili- ' 

 tate the comparison of our American flora with that of Europe, I 

 have appended the mark (Eu.) to those species which are indi- 

 genous to both. 



Distinction between Introduced and Indigenous Spe- 

 cies. Foreign plants which have become denizens of the soil have 

 to be described along with the genuine indigenous members of our 

 flora ; but the introduced species are distinguished by the specific 

 name being printed in a different type, namely, in small c^itals,* 

 while the na,mes of the indigenous species are in heavier, antique 

 letter.f Moreover, the cotlntiy from which they came is specified 

 (mostly Europe), as well as the nature of the denizenship. That is, 

 following the suggestions of M. Alphonse De CandoUe, I have clas- 

 sified our introduced plants as well as I could into two sorts, the 



* For example, under Ranunculus, R. EnLBOsns, ackis, &c., p. 43. 

 t For example, R, repens, on the same page. 



