I2 4 
Journal of Agricultural Research 
Vol. I, No. 2 
rot found in the top of a tree. It originates at the butt and travels 
upward in the heartwood of the tree. 
Of the sporophores of Polyporus berkeleyi found by the writer all 
occurred at the base of oak trees, either plainly growing from the exposed 
root or on the ground near the base of the tree. In the latter case a 
careful examination of the basal portion of the sporophore showed that 
it was attached to the roots of the tree. The writer has never found 
it growing on the bole of the tree above the surface of the ground, though 
it is not impossible that it could grow as brackets on the trunk, but it 
is doubtful if it does. P. sulphureus Fr. and P. schweinitzii Fr., two 
closely related polypores which produce heart-rots in living trees, are 
often found growing on the roots at the base of the diseased trees as well 
as on the boles proper. 
There was no evidence to indicate that the fungus could fruit on the 
trunk after the trees were felled, even if the rot should continue to 
grow in the felled tree. A small sporophore was found at the base of 
a 20-foot white-oak snag, while a large sporophore was found at the 
base of a dead standing white oak, indicating that the fungus could 
continue to grow and fruit after the trees were dead. The only external 
evidence that trees are attacked by this heart-rot is the presence of the 
sporophores of the fungus on the roots. Sometimes the base of the 
diseased tree is slightly “swell butted.” This last character, however, 
is common to trees attacked by other butt-rots. 
This rot was found associated with the rot produced by Hydnum 
erinaceus in 7 trees, with the pocket rot caused by Polyporus pilotae 
in 3 trees, and with the rot produced by P. sulphureus in 1 tree. 
Hydnum erinaceus was repeatedly found attacking and completely 
destroying wood previously rotted by the following fungi: Polyporus 
berkeleyi , P. pilotae , Fomes everhartiij Polyporus hispidus , P. jrondosus, 
and P. dryophilus , but no evidence was found of its attacking the rot 
produced by P. sulphureus , although it was found associated with 
this rot in the same tree. Fresh sporophores of P. berkeleyi were com¬ 
mon during the latter part of August and probably could be found 
during September. No fresh sporophores were seen in December. 
The writer has also examined authentic material of Polyporus berkeleyi 
on the following hosts and from the following localities: “At base of 
white oak,” Canada; “on roots of living white oak,” Missouri; from New 
York, West Virginia, and Missouri no host was given; “from dead place 
near ground in living oak,” Pennsylvania; “on base of stump,” North 
Carolina; “on oak,” New York; “on chestnut,” New York; “at base 
of tree,” Ohio; “at base of ash stump,” Ohio; “at base of oak stump,” 
Pennsylvania; from West Virginia, Pennsylvania, Ohio, North Caro¬ 
lina, and Canada no host was given; “near roots of large oak,” Canada; 
and “under oak,” Massachusetts. Apparently this fungus is found only 
in America. The writer has never seen it growing on anything but oak, 
