Journal of Agricultural Research 
Vol. I, No. 2 
118 
section, where the delignified areas may usually be seen in the summer 
wood. The delignification may continue without much absorption of 
the cellulose till long white bands of cellulose are found lying alongside of 
the vessels. This formation of bands of cellulose is especially marked 
when an abundance of air and rain water can penetrate the rotting wood. 
Such a condition obtains in fallen logs with large hollows or cracks in them. 
If, on the other hand, the rot is in the center of the heartwood of a 
living tree, the small, oval-shaped cellulose patches increase in size, 
hyphae from the adjacent vessels gradually absorb the cellulose until 
lens-shaped cavities are formed which at first are filled by a dense growth 
of rather coarse hyaline hyphae. The sides of these cavities ar£ lined 
with the projecting ends of the delignified wood fibers much like the rot 
produced by Trametes pini. Later both the hyphae and the cellulose 
lining may disappear and leave an empty cavity, thus producing a 
pocketed or honeycomb type of rot. 
In the earlier stages of the rot the diseased heartwood surrounding the 
white cellulose patches is of a cinnamon color. The wood at this stage 
of the rot is rather firm, contains small cellulose patches (PI. VII, fig. 6), 
and has vessels filled with colorless hyphae from 6 to io//, or even less, 
in diameter. The white, cellulose, oval areas gradually encroach upon 
the summer wood till they extend from one annual layer of vessels to the 
next. By this time much of the cellulose has been absorbed, and small, 
distinct cavities are formed. At this stage of the rot the diseased wood is 
much lighter in weight and can easily be broken into pieces between the 
fingers. Finally, a condition is reached in which the reddish brown 
rotten wood is very loosely held together and tends to split up into con¬ 
centric sheets corresponding to the annual rings. Short oval holes run¬ 
ning radially through two or three annual layers of wood are also common 
at this stage. In rare cases the cells surrounding the vessels are com¬ 
pletely absorbed, while the summer-wood fibers are delignified without 
the formation of cavities. Many of the trees attacked by this fungus had 
hollows in them, but whether the hollow was caused by this fungus or by 
a subsequent attack of another fungus, as Hydnum erinaceus , could not 
be determined. While this rot is a butt rot of the chestnut, it is also able 
to enter through dead limbs and thus produce a top rot. The rot when 
it enters by means of a dead branch follows the heartwood of the branch 
down to its juncture with the heartwood of the tree. The fungus then 
travels both upward and downward in the bole of the tree (PI. VIII, 
i). 
Of the chestnut trees in the region examined around New Berlin, 
N. Y., fully 75 per cent had tops attacked by this fungus. This large 
percentage was probably due to numerous dead limbs on each tree, thus 
affording the fungus ample opportunity to enter the tops. Of 302 felled 
chestnut trees which were studied by the writer in this region 119, or 
39.4 per cent, had this rot in the butts. This large percentage of infection 
