DECAY OF THE ‘‘BLUE™ WOOD. 29 
the Black Hills Forest Reserve where the beetle attack took place some 
four or more years ago there are thousands of dead trees standing with 
their tops broken off much like those shown in Pi. XII. In this view 
the tops can be seen lying on the ground. PI. XIII, fig. 1. shows the 
lower end of one of these tops. One will note how sharp it has broken 
off—almost straight across. One of the sheets of mycelium has curled 
over at the extreme right of the figure. The cross sections of such a 
top (reproduced on Pl. XI, figs. 1 and 2) show how completely the wood 
has been destroyed and that there is small chance for such a top remain- 
ing on the tree very long. 
Where the *‘red-rot” fungus attacks the tree at its base it brings 
about the decay of the larger roots underground, and also of the sap- 
wood. of the trunk close to the ground (PI. VI, fig. 2, large section, 
and Pl. XI. fig. 3). After a time the roots become weakened to such 
an extent that they are no longer able to keep the trunk in an upright 
position, and the result is that the tree is blown over. Such a fallen 
tree is then attacked rapidly at all points by the *‘red-rot” fungus, 
and in a few years nothing is left of it but a pile of rotted wood. 
When the wood has been completely destroyed the fruiting organs 
of the *‘red-rot” fungus begin toform. Some of the hyphe grow out 
through the bark and form a flesh-colored knob (Pl. XI, fig. 1), which 
rapidly increases in size and turns reddish in color. This knob grad- 
ually widens horizontally, forming a shelf, and on the lower side of 
this shelf numerous pores appear. One of these bodies is seen grow- 
- ing out from the fallen top shown on Pl. XIII, fig. 1, a little below 
- and to the right of the small branch extending out toward the front 
of the picture. (See also Pl. XI, fig. 2, and Pl. XIII. fig. 2.) Aftera 
year a mature fruiting body or sporophore (commonly called a punk, 
mushroom, or toadstool) has developed, from which spores are dis- 
charged at intervals. These spores are formed in the small tubes 
found on the lower side of the sporophore, and on a quiet night one 
can see them coming from the sporophore in white clouds as they are 
being discharged in countless thousands. The spores are so light that 
they are carried many miles by the winds and lodge on every stick and 
tree in the vicinity. 
The sporophores of this fungus may grow for many years. At dif- 
ferent periods, the length of which is not yet definitely known, they 
add a ring on the outside and thereby increase in size. The one shown 
attached to the section on Pl. XI, fig. 2, is probably 2 years old, while 
the one at the base of the tree on Pl. XIII is probably several years 
old. The sporophores may occur singly or in groups of two or three 
together. When a top falls so as to lie close to the ground where it 
is likely to be kept wet, the sporophores wil] develop every few inches, 
so that there may be as many as 20 or 30 ona log 10 feet in length. On 
