24 
DIVISION I.—GENERAL MORPHOLOGY. 
end. Agaricus melleus is chiefly a parasite on living European Abietineae (see 
Division II). 
It makes its way into the roots or the base of the stem beneath the 
ground, and the mycelium spreads in the cambium zone and in the young bast, forming 
M 
U: 
ji 
N 
FIG. 10. Agaricus 
of the growing apex oO: 
f 

FIG.9. Agaricus melleus. Me- 
dian longitudinal section through 
the growing apex of a 
nean mycelial strand, seen by trans. 
mitted light. Magn. 40 times. 

THE 
ne 
Hl 




es f 
Y 
un 
AN N a 
it 
cil we 
\ hen 
a J 
\\ x 
N Ihn 
NN Ph, 
nL 
a TRO N hs hi 
N 
N 
melleus. Thin median longitudinal section through the extremity 
f a subterranean mycelial strand, Magn. 250 times, but the Srawing 



d under higher magnifying power. 
compressed or membrane-like expanded networks of strands at the cost of the sap- 
containing layers of tissue, and also sends 

T 

FIG. 11. Agaricus dee section 
young branch of a subterranean mycelial strand in about the 
lower half of Fig. 9. «the axile large-celled tissue passing 
the outside into the later-formed rind. The outer limit of the 
rind is at 4; outside 5 is the covering of gelatinous felt with 
ding hair-like b hes A. Magn. 190 times. 


out a large number of single hyphae from 
these strands into the rind and wood, and 
especially into the medullary rays, where 
they spread widely. From these zni/ra- 
matrical, especially subcortical, parts other 
strands may proceed which develope as 
extramatrical strands usually in the soil, 
and are therefore sué/erranean, and branch 
and spread the Furigus over wide distances 
from one tree to another. These strands 
become more than 3 mm. thick and are 
round on the transverse section; they can 
also develope into enormous masses in 
moist rotting timber. 
The cylindrical subterranean strands 
consist when fully formed of a dark-brown, 
brittle, usually smooth peripheral tissue or 
rind enclosing a white finely-felted me- 
dulla. The rind, which in stout specimens 
has the thickness of paper, is formed in 
its outer portion of about twelve or more layers of cell-rows (hyphae) running down the 
length of the strand, and connected with one another laterally without interspaces, 
