>iii PREFACE. 



very few obscure species is added the following 

 mark, (-f) r. v. Occasionally added, signifies that 

 such plant had been seen alive by the author. And 

 7'. a. In a dried state. 



Anxious to restrain the limits of this publication 

 within the bounds of a portable manual for the student, 

 and to confine myself as much as possible within the 

 sphere of actual observation, the lower orders ofCryp- 

 togamia, now becoming a partial and particular study, 

 have been omitted, and the rather as they have been 

 minutely attended to by Z. Collins, Esq. and the late 

 Dr. Muhlenberg in his Flora Lancastriensis, which will 

 shortly be published. 



Philadelfihiay 7 

 I, 1818. 3 



May 27th3 



