94 Tuckerman's Enwmeration of 
we know, I must yet repeat that nothing here pretends to be 
more than the present amount of — of a single 
observer. 
Our alpine and mountain lichens may properly be com- 
pared with those of the Scandinavian Peninsula and Scotland. 
Of the first tribe, P4RMELIACEZ, of Fries, ten genera oc 
cur in the European district, of which eight are at present 
known in and about the White Mountains. 'To take up in order, 
the genera of this tribe — the forms of I. Usnea, reduced now 
by Fries to varieties of a single species, occur also, though to 
some degree modified, with us; while we have also the 
luxuriant U. longissima, not as yet found in Northern Europe. 
VERNIA’ is represented in the European district by 8 
species, one of them disputed and little known; while we 
have 4 species. II. RawarrNa has 5 species belonging to 
Scotland and Sweden, (but of these 2 are maritime ;) in our 
mountain district I find only two. Of IV. Cerrarta, 10 species 
occur in the European region, and the same number in ours, 
though of these last 3 are peculiar to America. V. Nernnon 
is represented abroad by 4 species, all of which occur als 
with us. VI. PErrTiGERA has 7 species of which we have sit. 
VII. SoLorına has 2 species, of which, though both ar 
now known to be American, neither has as yet occurred at 
the White Mountains. Of VIII. Sricra, there are known in 
the European district 8 species, in ours five. IX. PARMELIA of 
which large genus about 87 species occur in Scotland and 
Sweden, many of which are however maritime or otherwise 
limited, or rare, while we can reckon at present about 5L 
And X. GvarEcTA has in Scotland and Sweden 2 species 
neither of which is as yet known here. 
Belonging to the second tribe LECIDINE 2, of Fries, there 
are 5 Genera in the European district referred to, all of whi 
are found in ours... Of the Genera of this tribe, STEREOCAULON 
-1 Reference is made throughout this paper to the Lichenographia of 
Evernia as there constituted, contains not only the species upon which me 
; , but species also of Diod, Alectoria and Cornicularia- 
