June, 1955 
cuts to distances up to 2 feet back under 
the intact bark. Such patches of mycelium 
sometimes measured as much as 8 inches 
in width. 
Wound-stimulated mycelial growth 
was most prevalent during April and 
May. On any tree that had the fungus 
odor beneath the bark, macroscopic growth 
could be induced to form merely by lift- 
ing a section of bark and immediately 
nailing it back in place. From the trunk 
of felled tree R-7, six pieces of bark, each 
measuring approximately 8 by 12 inches, 
were lifted. On two of the areas from 
which the bark had been lifted, the bare 
wood was covered with thin plastic, and 
the bark was replaced and nailed down 
securely. On two other areas, the inner 
bark surfaces were covered with plastic 
and nailed back over the wood. On two 
other areas the bark pieces were only lifted 
and immediately nailed back in place. 
On the areas where the wood was cov- 
ered with plastic, abundant growth of 
Endoconidiophora fagacearum appeared 
within 2 weeks on the under side of the 
bark only. two weeks later this growth 
was old, but still no mycelium had formed 
on the plastic-covered wood beneath. On 
the areas which had the inner surface of 
Curt: Oak WIT INOCULA 303 
the bark covered, growth appeared on 
both bark and wood, more abundantly on 
the covered surface of the bark than on 
the wood. On the areas where bark was 
simply lifted and replaced, good growth 
occurred on both bark and wood surfaces. 
Similar results were obtained on felled 
tree R-8 and on several standing trees. 
Wounding not only stimulated free 
mycelial growth, but it also often hastened 
the development of typical mats with pads. 
For typical mats to appear adjacent to 
previously made cuts was common during 
April and May. In many cases the pads 
pushed the bark out at the edges of the 
cuts, exposing the mats to the outside. 
Also, mats appeared first on some trees 
at points where large nails had been 
driven through the bark in the process of 
building ladders on the trunks. These 
observations indicate that mat formation 
is stimulated by additional air from the 
outside. 
Mats on Bark on Forest Floor 
From November, 1952, through July, 
1953, 213 bark pieces and 128 wood 
pieces were taken from wilt-killed oaks 
and placed on the forest floor in four 
= 
Fig. 15.—Mycelial mat of Endoconidiophora fagacearum formed on a piece of bark from 
a wilt-killed oak while the bark lay on the forest floor. 
