200 E. Tuckerman on North American Listens. 
local on the western side of the continent, or it would have been 
met with before. When this remarkable plant was known to 
occur only in Eastern North America and Eastern Australia, 
it made the strongest case in favor of double creation that perhaps 
as ever been adduced. But since it has been found to occur 
throughout the Eastern Himalayas and in Japan, and has now — 
been detected i in Northwestern America also, the case seems to 
crown the conclusions to which this memoir arrives. 
Art. XXT.—& settee to an Enumeration of North Avast 
Lichens, continued ; by EDWARD TUCKERMAN, A: M., Professor 
of Botan ny in Amherst College. 
THE species follow each other, as before, in the onder of the 
arrangement proposed by Dr. Nylan nder , who has, studied these 
plants in the fight afforded by a knowledge which includes not 
only the external, but all the “pepe are details. Some spe- 
cies, not North American as yet known, but of more or less 1D- 
terest.in connection with our flora, are added in brackets. 
CoLLEMA APALACHENSE, Tuck. in litt., thallo stellato multifido 
imbricato crassiusculo fusco- viridi, laciniis is plano-convexis apice 
subteretibus obtusis rugulosis, subtus pallidis; apotheciis innato- 
sessilibus planis rufescentibus margine integerrimo. Spore ellip- 
solide 3-septate diam. vix duplo mises Lime-rocks, Han- 
cock county, Alabama, Hon. 7 
CoLLEMA TEXANUM, a pasties aes orbiculari aioe 
ce rere crasso aie -virescente, laciniis radiantibus elongatis 
subplanis profunde Cinna noes s papulosis; apotheciis sparsis 
planiusculis rufis margine po we mer. Spore minime fusi- 
bles the more perfect fori. of C. pulpos um. Spores xceed- 
ingly small. I am indebted, for their detection and eceon 
to my friend, the Rev. J. L. ae 
LEPTOGIUM CRENATE LLUM, = no , thallo imbricato_ tener: 
Le EPTOGIUM JUNIPERINUM, Tuck. in litt., thallo = subor- 
biculari imbricato tenui plumbeo e lobis rotundatis adscendenti- 
boos crenatis subtus ad margines albo-fibrillosis ; - theciis sesili- 
‘bus plano-convexis mnarpine tenui demum evanido diseum rufo- 
tre fa ae gia" eae ect S-septate. 
