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in Greenland (J. Vahl, e Th. Fr. 2. c.). ——Comparable with the last in 
size at least, as respects all but the spores, is B. fuscescens (Sommerf.) 
Fr., the flat, blackening apothecia of which, and the blackening hypo- 
thallus, associate the lichen, at first sight, with minute forms of Lecidea 
enteroleuca, or Buellia parasema, for which it may possibly be passed 
over. This appertains also, primarily, to the arctic zone, growing 
especially on birch-bark, and has been found in North America only in 
Greenland (J. Vahl, e¢ Th. Fr. 0. c.)-——B. exigua (Chaub.) Fr., is not 
unlike B. fuscescens, but its range is much wider, the lichen occurring 
commonly throughout the United States. The fruit of this also at length 
blackens, when it is sometimes difficult satisfactorily to distinguish it 
from minute conditions of Lecidea enteroleuca; to which species Nylan- 
der (Prodr.) referred the present. — B. Nylanderi, Anz. Catal. Sondr. 
p. 75 (Lecidea fuscescens, Nyl. Prodr., L. fuscescens, v. leprodea, Nyl. 
Lich. Scand. p. 213) inhabiting pine bark in France and Italy, and 
occurring to me here (on Pitch-pine) in Cambridge, Massachusetts, as, on 
the same bark, at New Bedford, to Mr. Willey, appears certainly to be 
well distinguished. The plant is comparable, generally, with some small 
conditions of B. rubella, but has globular spores. ——B. uliginosa 
(Schrad.) Fr., is very common, according to Fries, in Europe; and may 
prove so here, though easily overlooked. JI have found it on the earth in 
the alpine regions, as well as on the charred surface of old pine stumps, 
in the White Mountains, and on the earth in Watertown; and Rev. Dr. 
Curtis has sent me excellent specimens (agreeing exactly with one of 
those, on a similar soil, in Moug. & Nestl. Cr. Vog. n. 747) from North 
Carolina; and Mr. Hall, from Illinois. ——B. riviulosa (Ach.) Fr., is com- 
mon on granitic rocks in New England, but (the fruit soon blackening) it 
may easily be passed over for a Lecidea. Spores of the common low- 
country lichen oblong, at length a little curved, or bean-shaped. Alpine 
specimens however (White Mountains) which appear also to be at length 
distinguishable by a thickened, strongly chinky thallus, made up of large 
areoles, exhibit smaller, roundish-ovoid spores; and may well be referable 
to the var. mollis, Wahl. (£1. Lapp. p. 472) which is Lecidea mollis, Nyl. 
Lich. Scand. p. 223. And there is also to be mentioned, as a member of 
the same cluster, a bark-lichen, according to Fries only a corticoline form 
of B. rivulosa, as it ranks also in Nyl. Lich. Scand., but distinguished by 
others as B. Lightfootii, which has been detected, on Hemlock, in Massa- 
chusetts (the specimens agreeing pretty closely in most respects with the 
foreign ones) by Mr. Willey. ——B. quernea (Dicks.) Fr., closely simu- 
lated by a condition of our form of Lecanora elatina, which form was 
indeed referred to itin Syn. Lich. N. Eng., proves to be one of that inter- 
esting group of European lichens which is confined, in North America, to 
the Pacific coast. Mr. Bolander’s specimens agree entirely with the 
European. The exciple, in these specimens, is by no means originally 
immarginate, as asserted by several recent describers, especially Koerber 
