544 
Journal of Agricultural Research 
Vol. XXIX, No. n 
allows secondary fungi to enter more 
easily through the cracks. Table III 
shows the results of these cultural 
experiments. Figure 3, C and D, shows 
how the selection of inoculum fragments 
is made to‘extend from the typical de¬ 
cay to the sound areas. As a general 
rule the apparently sound regions be¬ 
yond the incipient discolorations in the 
brown rots contain viable hyphae. 
Table III .—Distribution of hyphae of various fungi in infected wood as determined 
by various cultures 
[4 indicates positive cultures; 0 indicates negative cultures] 
Fungus or rot 
Host 
Appar¬ 
ently 
sound; 
normal 
color 
Ceratostomella __ 
Echinodontium tinctorium. 
Fomes applanatus _ 
Do_ 
Fomes fraxinophilus _ 
Fomes igniarius _ 
Do...... 
Do_ 
Do_ 
Fomes lands _ 
Fomes pinicola _ 
Do__ 
Fomes roseus ... 
Do__ 
Ganoderma tsugae _ 
Do_ 
Lentinus lepideus _ 
Lenzites sepiaria _ 
Pholiota adiposa .. 
Polyporus adustus _ 
Polyporus amarus _ 
Polyporus anceps _ 
Do.__ 
Polyporus balsameus _ 
Polyporus ellisianus. . 
Do_ 
Polyporus schweinitzii _ 
Do_ 
Do_ 
Polyporus sulphureus . 
Do_ 
Schizophyllum commune.. 
Trametes carnea ... 
Trametes pint.... _-_ 
Do....__ 
Do__ 
Do_ 
Do_... 
Trametes serialis _ 
Brown butt rot; pocket 
rot. 
Brown cubical rot_ 
Pinus strobus __ 
Tsuga heterophylla .. 
Acer saccharum _ 
Populus grandidentata _ 
Fraxinus americana. . 
Populus sp___ 
Acer rubrum ... 
Prunus emarginata .. 
Populus tremuloides. . 
Pseudotsuga taxifolia . 
Tsuga heterophylla .. 
Tsuga canadensis __ 
Picea canadensis... .. 
Pseudotsuga taxifolia _ 
Tsuga canadensis _ 
Tsuga heterophylla _ 
Pinus banksiana _ 
Picea canadensis. . 
Tilia americana _ 
Liquidambar styraciflua _ 
Libocedrus decurrens _ 
Picea canadensis __ 
Pinus banksiana .. 
Abies balsamea .. 
Pinus ponderosa .. 
_do__ 
Picea sitchensis _ 
Larix decidua ___ 
Pseudotsuga taxifolia _ 
Quercus sp___ 
Pseudotsuga taxifolia _ 
Betula papyrifera __ 
Picea canadensis .. 
Pinus banksiana .. 
Pseudotsuga taxifolia . 
Pinus monticola .. 
Pinus strobus ... 
Larix laricina __ 
Pseudotsuga taxifolia .. 
Thuja plicata _ 
Thuia Occidentalis .. 
8 4 
4 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
+ 
4 
0 
0 
4 
0 
0 
0 
0 
0 
0 
4 
0 
0 
4 
4 
+ 
0 
0 
4 
4 
0 
0 
0 
0 
0 
0 
0 
0 
Incipient rot 
Typical rot 
Faint 
; color 
Dis¬ 
colored 
Edge 
of 
pocket 
Center 
of 
pocket 
Badly 
rotted 
area 
i 
| + 
4 
t 
+ 
+ 
4 
! 4 
+ 
4 
4- 
4 
+ 
i + 
4 
+ 
I fc 0 
4 
1 
4 
i ° 
4 
4 
4 
4 
i 0 
4 
4 
i 4 
4 
4 
j 4 
4 
4 
] + 
4 
4 
j 
4 
4 
4 
4 
4 j 
4 
4 
i c 4 
4 
4 
I 4 
+ 
4 
! 4 
4 
4 
1 4 
4 
4 ! 
4 
4 
j 4 4 
« 4 
j 
4 
4 
+ 
1 
4 
4 i 
4 
! + 
4 
4 | 
4 
1 "i* 
4 
I 
4 
! + 
4 
f 
4 
! 4 
4 i 
:__ 
4 
! 4 
4 
4 
I / 4 
4 
4 
| 4 
1 4 
4 
4 
1 + 
4 
f- 
! 4 
a -f 
4 
i 4 
4 
4 
+ 
! + 
4 
4 
4 
4 
1 0 
4 
4 
4 
4 
h 0 
4 
4 
4 
4 
I 
+ 
+ 
4 
! 4 
4 
4 
4 
I + 
4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
4 
a White area adjacent 6 Yellow, 
to stained area. Water-soak. 
4 Red brown. f Rare. 
e Black brown. 0 Brownish. 
Table III shows 8 of the fungi with 
positive cultures from the normal col¬ 
ored areas, 22 from the faint colored 
areas, 24 from the discolored areas, 9 
from edge of pocket, and 24 from the 
typical rot areas. Only one case 
(Polyporus ellisianus) did not give 
cultures from the late typical stage of 
rot. The results with Trametes pini 
are interesting and indicate that hyphae 
do not develop beyond the outer edge 
of the incipient discolorations. This 
also appears to be true for Polyporus 
anceps in Pinus ponderosa and Pinus 
banksiana , and for Polyporus circinatus 
in Picea canadensis. The point to be 
emphasized here is that the hyphae of 
certain fungi, many of which produce 
brown rots, do extend some distance 
beyond the definitely discolored areas 
which are usually recognized as stages 
of incipient rot. The average distance 
to which these hyphae penetrate ahead 
of the discolorations in each case can 
be obtained only after many tests of 
freshly cut material. 
THE EFFECT OF HYPHAE ON THE WOOD 
TISSUES 
Methods of cell wall penetra¬ 
tions. —One of the earliest writers to 
figure the penetration of cell walls by 
fungous threads was Unger (80), who 
clearly showed the constriction of the 
hyphae in passing through the bore 
