THE LARCH CANKER 45 
to each other. Further evidence, however, would be neces- 
sary to substantiate this view. 
For a fusion to take place it is of no consequence whether 
the two hyphae are branches of the same mycelium or not, 
and a number of spores germinating together form a close 
network in which it is impossible to determine from which 
Fig, 21.—The growth of mycelium in drop cultures: sp., spore. 
spore many parts of the mycelium have arisen. Such a net- 
work is best seen in cultures in distilled water, as until the 
hyphae become starved the fusions are not so frequently 
formed. 
In such cultures the primary germ tubes become markedly 
septate (fig. 21, B), the septa being usually 12-20 apart. 
But the branch hyphae which arise from these are often quite 
unseptate, and septa, when present, are far apart. As the 
available food supply is used up, drops of some liquid 
(probably an oily substance) appear, which become more 
numerous as the segments die. I have often noticed that 
some segments die before others and lose their turgidity, 
and then the more turgid ones are markedly refringent and 
