Peltigera polydac- 
tyla (Neck) Hoffm. 
Fie:. 2. Thallus large, 
very smooth and thin, 
with a somewhat pol- 
ished surface; the lobes 
are broad and round 
with slightly crisped 
margins. The color is a 
bright grass green, 
becoming lead color or 
brown when pressed. 
The under side is light 
brown, with tufts of 
dark brown fibrils, the 
reticulated veins are a 
light brown, turning 
much darker toward the 
center. 
The apotheciaare 
usually large and revo- 
lute, digitately clustered 
and are borne on the extended lobes of the thallus. The disk is reddish 
brown, with a crenate margin of lighter color. The habitat of this species 
is rocks and decaying wood; it is a common one throughout the United 
States. 
Peltigera scutata (Dicks.) Leight. The thallus of P . scutata is small, 
quite thin and somewhat rough; the color is a dull green, becoming a light 
reddish brown. The lobes are narrow and crisped, with frequently gray 
soredia on the margins. The under side is almost white with light brown 
veins which forms a spongy nap. 
The apothecia are small and are found on the short and somewhat scat- 
tered lobes of the thallus ; the disk is a dark, dull brown. 
P. scutata is found on rocks and earth with mosses. It is not a rare 
species, but not so common as many others of the Peltigeras. 
Peltigera pltlverulenta (Tayl.) Nyl. Thallus not as large as in P. 
polydactyla , it is furrowed and pitted, thin and somewhat granulated, has 
short, crisped lobes. In color is a grayish green, soon turning to a greenish 
brown. The under side is light brown, with veins of the same color which 
toward the center coalesce, forming a close nap. 
The fertile lobes are narrow and compressed, on these are borne the 
medium sized apothecia, which are round, with dark brown disks : fruiting 
specimens are rare. 
P. pulverulenta is found in both the Eastern and Western States, but 
is not a common species; it grows on rocks and earth in very moist localties. 
Peltigera rufescens (Neck.) Hoffm. This species so closely resembles 
