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The apothecia are small and crowded, with a deep red disk which has a 
thin entire margin. 
Found on trees and decayed wood: quite common throughout the North- 
ern States. 
Collema nigrescens (Huds.) Ach. var. leucopepla Tuckerm. This 
variety is more common than C. nigrescens , especially in the Southern 
States. The thallus, which is orbiculate, is a little thinner and more 
wrinkled, but the chief macroscopical difference is in the apothecia which 
are very small and crowded, with a convex disk which is white pruinose, giv- 
ing a very attractive appearance with the often perfect outline of the thallus. 
Collema pulposum (Bernh.) Nyl. Thallus medium in size with crowded 
lobes which are crenate at the margin, rather thick and frequently granulose 
toward the center. It is a dull dark green and is very gelatinous when 
damp. 
The apothecia are large and flat with a deep orange colored disk, the 
margin is raised, is very thick and almost black. 
C. pulposum is found imbedded in moss in calcareous earth, or on lime- 
stone rocks; more common in the Western than in the Eastern States. 
Leptogium muscicola (Sw.) Fr. Thallus very minute and moss-like, the 
interwoven branches are irregular and much branched. In color it is almost 
black, with a varnished look. 
The apothecia are rather large with a flat brown disk which is somewhat 
appressed, the margin is thin and entire. 
This interesting little lichen grows over mosses and is difficult to 
separate from them. It grows in mountainous regions, both in the East and 
West, but is more common on the Pacific coast. 
Leptogium lacerum (Sw.) Fr. Thallus rather small with rounded lobes 
which are much wrinkled and crowded, and whose margins are very irregu- 
larly cleft into jagged, fringe like edges. The color of the thallus is a dark 
dull brown when dry, a dark lead color when moist; the under surface is 
paler with hair-like rhizoids with which it clings closely to the substratum. 
Found on rocks, frequently with mosses; common in the Northern and 
Middle States. 
Leptogium palmatum (Huds.) Mont. Pl^f^VI. Fig. 3. Thallus medium 
with narrow, convolute lobes which have obtuse tips; these are more or less 
wrinkled and pitted, the edges are fringe like. The color is a deep reddish 
brown, with a trace of the lead color, found in all species of Leptogium. 
The apothecia are very small and sessile, somewhat concave, the disk is 
a dark red with a light red entire margin. L. palmatum is found on earth 
growing with mosses in British Columbia and the Western States. 
Leptogium pulchellum (Ach.) Nyl. Plate VI. Fig. 4. Thallus 
medium with thin round lobes which are somewhat wrinkled and plicate; is 
a dark lead color with a greenish tinge when moist. It clings closely to the 
substratum except at the edges where it curls over slightly. The under side 
is a little ligher in color, is pitted and wrinkled. 
