366 CONNECTICUT EXPERIMENT STATION REPORT, IQI2. 
Often, after trees are cut, the stumps of those infected at 
the base develop a vigorous growth of the fruiting stage on 
the three or four outer rings of wood. This probably means 
that the mycelium can penetrate thus far into the wood from 
the canker, or possibly it may mean that fresh infection takes 
place from spores developing in the nutrient material furnished 
by the exposed sapwood. 
After an infected tree has been killed, or has been cut 
before death, there may be a further development of the 
fruiting stage of the fungus. We doubt, however, if disease- 
free trees often develop prominent infection after cutting. In 
other words, the fungus is parasitic or semi-parasitic, but does 
not develop in its prime as a saprophyte. Even on trees killed 
suddenly and left standing, Plate XXII b, we have often failed 
to notice a general spread of the fungus through the bark. 
In the wood pile, too, while the fruiting stage no doubt shows 
some increase, a general subsequent infection of the disease-free 
bark does not seem to take place. 
As to the Fungus. The mycelium of the fungus ramifies 
through the bark, beneath it, and often into the wood for a 
short distance. When the epidermis of a young, smooth, 
cankered branch is carefully peeled off, it often shows the 
mycelium as a whitish or yellowish coating just beneath, and 
below this is the reddish-brown diseased bark sharply marked 
off at its edges from the healthy white tissues. In the older 
infected bark, the mycelium is sometimes seen as fan-shaped 
areas between the tissues or on the wood. The mycelium often 
gives a mottled effect to the bark as seen when cut through. 
In time, with the aid of insects, it produces’ soft, semi-dusty 
spots in the ‘firmer, less affected tissues. 
The infected tissues do not show external signs of the fungus 
itself at first (with artificially inoculated cankers, not for two 
months or more after inoculation, Plate XXV b), but in the 
smooth bark in time numerous fruiting pustules are gradually 
protruded through small, lenticel-like openings. These at first 
are quite small, but in time show as subspherical to irregularly 
oblong cushions one-eighth of an inch or less in length and 
about that in height, XXIVc. In the rough bark they break 
out more irregularly from the crevices, and are more run 
together into compound groups, XXIV d. They vary in color 
