THE LARCH CANKER 49 
MYCELIUM AT DIFFERENT TEMPERATURES 
hours. Three days. Fifteen days. 
Average Average 
length length 
of those Number | of those 
measured. | Remarks. | Longest. | measured. | measured. | Remarks. Remarks. 
175 p Very 650 9 440 p — United into band 
many 1-5-2 mm. 
germi- « across. Very 
nated thin growth. 
346 pw Very — _ = Large United into band 
many branch- | 4-5-7 mm. 
germi- ing across, Very 
nated masses close dense 
700- growth. 
1,000 » 
across 
161 2 Very 240 uw 10 206 | Very Temp. of incu- 
many much bator not con- 
germi- branched| stant, so statis- 
nated. tics valueless. 
Very 
much 
branched 
twigs of other conifers in damp chambers. The conifers 
which I experimented with were spruce, silver fir, Scots 
pine, and Corsican pine. In all these the mycelium grew 
freely, and on silver fir apothecia were produced. 
Cultures were also obtained on sterilized leaves of larch, 
spruce, and Scots pine. These showed no tendency to grow 
for several weeks; but ultimately masses of dead leaves 
became covered with mycelium, and on sectioning the needles 
hyphae were found to have ramified the mesophyll, though 
they had not penetrated into the vascular bundle region. 
This shows that the mat of dead larch needles lying on 
the floor of larch plantations forms a suitable substratum 
for the mycelium of Dasyscypha, and the mycelium which 
is commonly found growing on these needles may belong to 
this fungus. It is not suggested that the fungus can reinfect 
the trees by this means, since no fructifications are formed. 
But it may assist in the decomposition of the foliar débris. 
Artificial infection with the canker fungus. The first 
1888 E 
