[Vor. 1 
258 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
occur; in faet, the right-hand trunk of the lower tier in pl. 9 
fig. 2 has very little live wood left. 
After the mycelium has reached the bark it grows through it, 
and fruiting bodies develop on the outside. Тһе latter some- 
times occur singly, but more commonly in linear groups parallel 
to the long axis of the trunk. Frequently one or more fruiting 
bodies grow out from the holes made by the borer. In the 
right-hand trunk in pl. 8 fig. 1 sporophores are shown growing 
out at the base of vigorous, live shoots; in the left-hand trunk 
the shoot is dead, having been killed during the year as the 
fungus invaded the wood from which the shoot was growing. 
The sporophores found were typical of Polyporus versicolor L. 
This fungus is so common on the dead wood of various hard- 
woods that a detailed description is hardly necessary. It is 
interesting to note here that this is the second instance where 
this fungus attacks living plants. In the case of the catalpa the 
fungus grows vigorously only in the live tree; infected wood 
rarely, if ever, is decayed after itis cut from the tree. Many 
thousand posts of catalpa, the heart of which had been partially 
destroyed by Polyporus versicolor, have served as fence posts 
during the last ten years without showing a sign of decay of that 
part of the wood which was sound at the time of cutting. With 
the lilac it is different; the dead wood is just as subject to attack 
as is dead oak, beech, or gum wood. 
The age at which lilac bushes are attacked has not been defi- 
nitely determined. Those examined were about 15-20 years old 
(23 inches in diameter). The trunk shown in pl. 8 fig. 2 was over 
thirty years old. It is probable that the disease is not serious 
until the bushes are ten or more years old, although this will 
depend somewhat on the rate of growth. Trunks 11-2 inches 
in diameter were frequently found diseased. The effect of the 
disease is to gradually kill the top of the trunk; side shoots then 
develop farther down, which in turn are killed by the fungus, 
and eventually the trunk is broken off by the wind or snow. 
The prevention of the disease is possible by continued atten- 
tion to the borers. A careful examination for the latter should 
be made in June or July, and if any are present these should be 
killed by means of a wire, and the holes—after antiseptic 
treatment with some coal-tar compound—plugged. Painting 
