PREFACE. 
course has been had to the Herbarium=^ of the late 
Dr. Muhlenberg, in the American Philosophical 
Society, whereby all that certainty has been at- 
tained which a source so authentic could produce. 
The synonyms have been added to reconcile to 
the student, apparent confusion and incongruities. 
By the kindness of Mr. Nuttall, I have availed 
myself of the use of his work in quoting the genera. 
The enthusiastic devotedness of that gentleman to 
the study of American plants, and more particular- 
ly of their generic characters, are highly honoura- 
ble to his acumen, and his spirit of discovery 
and research; and have resulted in such a work as 
will doubtless accelerate a correct acquaintance 
with American Plants. 
* It is a matter of no little satisfaction that I mention as 
the property of the American Philosophical Society, this valu- 
able and authentic Herbarium consisting of Dr, Muhlenberg’s 
entire collection of American plants. The well-known cir- 
cumspection and patience of that botanist, and the length of 
time in which the herbarium was arranged, add greatly to its 
value as authority. 
It is but due to those concerned, to remark, that at a period 
when this herbarium was eagerly sought after, not only by 
persons in distant states, but by foreigners, it was proffered by 
the son of Dr. Muhlenberg, whose property it became, to Mr. 
Collins, for the American Philosophical Society, at a price con- 
siderably less than might otherwise have been obtained for it ; 
and this gentleman improving the occasion, promptly purcha- 
sed it with a view to its ultimate destination as a part of the mu- 
seum of that institution to which it has since been presented by 
Mr. Zaccheus Collins, Chief Justice Tilghman, Dr. Wistar, Dr. 
James, Mr. George Pollock, Mr. William Short, Mr. John 
Vaughan, Dr. Champan, and Dr. Dorsey. 
