THE FUNGI 255 
the soil, serves as food for the reindeer and is known 
as “reindeer moss.” 
Must iehens a ¢ CRIS OP SY 
sothabashof Goa, | aeRO S 
wy 
on rocks, or soil ee: aes Ge 
where they have lit- ox ACH) Spee ue v7 
tle moisture except ROE y DOES ee = 
5 US; 
during rainfall, but 
some grow where 
they are constantly 
wet. Some of the 
latter are gelati- 
nous. Most of the 
conspicuous lichens 
are foliaceous or else 
have a thallus com- 
posed of branching, 
cylindrical, thread- 
like portions. But 
many species, often Fie. 180. Transverse Section through Thallus 
less conspicuous, are of a Lichen (Sticta fuliginosa). (x 500.) 
crustaceous, grow- c, cortical or epidermal layer; g, gonidia; 
: i h, hyphe. 
ing as if they formed 
part of the bark or rock to which they are attached. 
PUCCINIA, ONE OF THE BASIDIA FUNGI 
328. Occurrence. — Puccinia graminis, wheat rust, is 
common on cultivated wheat and other grains and also 
on many wild and cultivated grasses besides the grains. 
Numerous species of rust are known. <A rust may have 
one, two, or three kinds of spores, and when three occur 
