NOTE. 



In this Flora analytical keys formed by the contrasting of 

 diagnostic characters precede the families, genera and species, 

 and a key to the orders precedes the main body of the work. 

 A description and a figure is cited for each species ; for exam- 

 ple, " Man. p. 469 " refers to a description on page 469 in Brit- 

 ton's Manual of the Flora of the Northern States and Canada, 

 while " II. Fl. /. 1753" refers to a figure in Britton ,& Brown's 

 Illustrated Flora of the Northeastern United States, Canada 

 and the British Possessions. Following the known geograph- 

 ical distribution of each species, is recorded its distribution 

 within the State, outlined by counties, as it was known to the 

 author. The outline map of Pennsylvania was drawn for this 

 work by Mr. Benj. H. Smith, who has also kindly read part of 

 the proof. 



