VI 
PREFACE. 
sparing in the citation of particular localities, and of the names of 
the botanists who have detected and kindly communicated rare or 
local plants. My restricted limits alone have debarred me from 
the pleasing duty of repeatedly making the acknowledgments 
which are justly due to many attentive and zealous correspondents 
throughout the country; and their daily increasing number ren¬ 
ders this appropriate expression more difficult, except in extended 
treatises. Those who think, as many may, that I should have 
allowed myself wider latitude in this respect, will at least for¬ 
give any apparent ungraciousness, when they find that this vol¬ 
ume, which it was firmly intended to restrict to 350 pages (and to 
have carried through the press last spring), has unavoidably ex¬ 
tended to more than twice that size. Especially do I regret that 
this unexpected bulk has compelled the omission of the family 
of Lichenes , after they had very carefully been prepared expressly 
for this work, in compliance with my invitation, by the well- 
known Lichenologist of this country, Mr. Tuckerman. Noth¬ 
ing but the apparent impossibility of including the whole within 
the covers of a single duodecimo volume, and the assured ex¬ 
pectation that it will immediately be given to botanists in another 
way, has reconciled me to the exclusion of this important contri¬ 
bution.* In a second edition I still hope to give, by means of a 
supplementary volume, and through the aid of accomplished col¬ 
laborators, not only the Lichens, but also the two remaining or¬ 
ders of the lower Cryptogamous Plants, namely, the Algce or 
Seaweeds , and the Fungi. 
The wide district which this compendious Flora embraces, 
although irregular in form, plainly belongs to one and the same 
* This contribution, in a more extended form, will soon be published in the Pro* 
ceedings of the American Academy of Arts and Sciences. 
