PREFACE, 
xk 
Bcreali-x^mericana” as near as possible, avoiding 
Carefully to change old established names, however 
faulty, unless in cases where good authority furnished a 
more appropriate one. As for example, I have adopted 
Fraxinus acuminata of Lamarck, instead of FraxinuS 
umericana 9 Linn., and Cynoglossum amplexicaule of 
Michaux for Cynoglossum virginicum y Linn. But I 
have never approved of such changes as Juglans alba 
and cinerea of Linnaeus to Juglans squamata and ca« 
ihartica , as the younger Michaux in his ee Arbres Fores» 
tiers” has done. This otherwise very useful publication 
is full of such new names, imposed on well known and 
long established species, and sometimes even without 
the least hint respecting their names in other authors. 
The specific characters in most instances have been mo- 
delled anew or altered as it was found necessary. Where- 
ever any alteration had been made it was necessary to 
quote the author from which the species had been taken 
in a separate line, as page 16 Monar da didyma % after 
the specific description I had to repeat that it was the 
same with M. didyma , Willd.sp.pl. 1. p. 125, To 
avoid this superfluous repetition, and save as much room 
as possible, I found it expedient to adopt, from page 72 
to the end, the following mark (— -), to be placed after 
the specific character whenever it had been amended ; 
so that Stipa avenacea , page 7 2, is the same species de- 
scribed by Willd. sp. pi. 1. p. 442, but the character is 
new or augmented. Wherever the author follows the 
.description without this mark, as page 73, S accitarum 
giganteum, Pers. eneh. 1. p. 103, in that case the cha^ 
jacter has been adopted without alteration, 
b 2 
