26 BULLETIN 360, U. S. DEPARTMENT OF AGRICULTURE. 
unusual habitat), Zrametes serialis Fr., and Lenzites sepiaria Fr. 
Fomes pinicola Fr. was found rotting the heartwood of living trees 
in three different cases and had entered its host through mistletoe 
burls 10 feet from the ground. Polyporus volvatus Pk. occurs fre- 
quently on the burls of larch and yellow pine. Several species of 
Thelephoracez were collected from the mistletoe burls, chief of which 
were Stereum sulcatum Burt, 
Corticium berkeleyi Cooke, 
C. galactinum (Fr.) Burt, 
and Peniophora subsul- 
phurea (Karst) Burt. Cera- 
tostomella pilifera (Fr.) 
Wint., the bluing fungus, 
appeared occasionally in the 
dead wood of the burls. 
Trametes pini affected 80 
per cent of all burls attacked 
by fungi. Since the most 
advanced stages of decay 
were always at the burl or in 
its near vicinity, it was as- 
sumed that the fungi had en- 
tered at this point.. The de- 
eay at or in the burl tissues 
was in most cases not con- 
nected with the decay which 
is often present in other 
parts of the trunk. The 
breakage of old branches 
possessing heartwood, 
through the accumulation of 
brooms at their outer ex- 
tremities, is likewise a means 
of fungi entering the tree. 
Fic. 25.—The soft spongy cortex of a mistletoe 
infection on lodgepole pine gnawed by rodents. 
This is a very common type of injury in mistle- Not infrequently Fomes 
toe-infected trees. ons A : 
laricis enters its host by this 
means. Mistletoe burls on Douglas fir are known to become infected 
with Z7rametes pini. A mistletoe burl on Alpine fir was found to be 
inhabited in one instance by Pholiota adiposa Fr. Meinecke (10, p. 
58) refers to the mistletoe cankers of Abies concolor as offering an 
easy entrance to germinating spores of H'chinodontium tinctorium. 
Burls on yellow pine, owing to their resinous condition, are seldom 
attacked by wood-destroying fungi. The bluing fungus, however, 
has been found by the writer in the distorted tissues of mistletoe 
burls on living yellow pine. 
