Nov. io t 1913 
Heart-Rots of Hardwood Trees 
127 
coarse, fibrous surface, due to the stiff unabsorbed ends of the vessels, 
partially isolated by the absorption of the wood fibers and the sub¬ 
sequent tearing apart by the saw when the tree was felled. This fibrous 
character was not evident except where the tree was sawed. 
This rot was identified in only 12 trees out of the 1,968 white oaks 
examined. No idea was obtained as to its age in a tree, as all of the trees 
found affected by it had open scars at their bases. It was apparently 
through such scars that the fungus entered the tree. Sporophores of 
Polyporus frondosus were found attached to the roots of 6 of the trees 
in much the same manner as those of P. berkeleyi , usually on that side of 
the tree which had the fire scar. The average height in the 12 trees 
attacked was 2.3 feet, the average diameter of the rot 12 inches from the 
ground was 14 inches, and the average age of the trees attacked was 270 
years. The minimum age of the trees attacked was 220 years and the 
maximum age was 340 years. The maximum diameter of the rot in a 
tree was 24 inches and the maximum height in the tree was 4 feet. 
The only external evidence of this rot in a tree was the presence of the 
sporophores attached to the roots of the diseased tree. The connection 
between the attached sporophores and the heart-rot in the tree was 
easily established in every case. This fungus may not continue to grow 
in the diseased trees after they are cut, for no sporophores have been 
found on felled trees nor have any been reported as occurring on logs. It 
seems to be strictly a butt-rot, as no evidence is known to the writer 
of its occurrence in the tops or on the branches of trees. One tree was 
found in which this rot was associated with the rot produced by Hydnum 
erinaceus. The writer has also found sporophores of P. frondosus on the 
roots of Quercus digitata at Arlington, Va., and has examined authentic 
herbarium material of the plant on the following hosts and from the 
following localities: “In evergreen woods,” Canada; “under oak,” 
Massachusettes; “at base of oak,” Massachusetts; “at base of red oak,” 
New York; from Ohio, no host given; “on old stump,” Ohio; “at roots of 
fallen oak,” Ohio; “at roots of oak,” Maryland; “on dead trunks, 
l Aceris negri,’ ” Missouri; “on roots of chestnut,” Germany; “on roots of 
chestnut,” Italy; “on Castanea vesca” France; “at base of large oaks,” 
Saxony; “at base of trunk,” Italy; and “on roots of chestnut,” 
Bohemia (?). 
This fungus, which has been known to mycologists for many years, 
is represented in nearly all the more complete lists of European fungi. 
It is evidently very widely distributed, inhabiting frondose woods in 
North America and Europe, in direct association with oak and chestnut 
trees. 
The writer is under many obligations to the officers in charge of the 
New York Botanical Garden for the many courtesies extended to him 
while there, and to Dr. W. G. Farlow for free access to the Cryptogamic 
Herbarium of Harvard University. 
