some Lichens of New England. 97 
have been able to determine is about 165. As the Leprarie, 
Spilomata, and Variolarie are excluded; and as a large 
number of Acharius’s species, heretofore universally received, 
are, in accordance with the Friesian Method, reduced to va- 
rieties, this number must be allowed to embrace probably 
much the largest part of the Lichenes of a region so limited 
as the White Mountains. ‘The comparison above attempted 
with Scotland and Scandinavia, might more justly have been 
made with a particular district in one of those countries, as 
Dovre in Norway, but for this I have not the necessary 
authorities. 
Usnea longissima, Ach. Lichenogr. p. 626., Ach. Syn. p. 
307., Fries Lichenogr. p. 19., in Obs., Parmelia longissima, 
Spreng. Syst. IV. 277. On firs and other trees, where they 
begin to diminish in height, on the mountains, abundant, and 
occurring five feet long. Frequent also at the base of the 
mountains in cold swampy woods. Distinguished by its 
terete, almost simple thallus, clothed with short, very regular 
horizontal fibres. Our plant agrees perfectly with the original 
Saxon lichen; and I possess what seem to be forms of the 
same species from South America, New Holland, Africa, 
Evernta ochroleuca, (Ehrh.) Fries Lich. p. 93., y. sarmen- 
fosa, Fr. l. c., Lichen sarmentosus, Ach., Parmelia, et de- 
— Alectoria, Ach. On the trunks and branches of 
= the mountain forest; resembling a pendulous Usnea. 
The rigid, fruticulose variety a, which was referred by Acha- 
"us to a different genus, has not occurred, though I have 
apa two specimens belonging to the species, which resem- 
ble it sufficiently to encourage further search. BS a 
Cernanra nivatis, (L.) Ach.— In fruit; found for the 
me the present season. Hooker says it has never oc- 
curred in this state in Britain. 
Peuricnra malacea, Ach. Syn. p. 240., Fries Lichenogr. P- 
— On the ground, and rarely on shrub firs, above the limit 
trees: Tt also occurs at a much less elevation, as in the 
VOL. v. ~ 
of 
