The Biology of Polyporus Pargamenus Fries 145 
This reticulum contained very little resistant woody sub- 
stance in most cases and consisted mostly of masses of intri- 
eately interwoven minute hyphe. Within the individual 
pockets even more partially decayed woody substance re- 
mained than in the decayed sugar maple wood studied. It 
would appear either that the decay does not progress so far in 
chestnut oak as it does in sugar maple wood, or that the 
original localization of the decay into pockets is in time 
overcome before the decay becomes completed, after which 
the subsequent decay progresses uniformly and involves the 
whole of the remaining woody substance. From the results 
obtained it would seem that the decay continues to progress 
longer and to become more complete in certain woods than 
in others. This irregularity is determined apparently by 
the resultant of the action of the hyphe of this particular 
fungus in conjunction with the inherent qualities of the 
wood attacked. In any event the last trace of the reticulum 
of resistant wood separating the pockets is found in the 
reticulum of matted hyphe remaining at the same point 
aftr the reticulum of resistant wood is destroyed. 
Just why the hyphz should collect into zones at these 
points is not clear. We know that in general in the decay 
of wood by wood-destroying fungi but comparatively little 
or scanty mycelium is to be found in the much-decayed por- 
tions of wood. This peculiarity is clearly evident within the 
pockets produced by Polyporus pargamenus and is very 
striking in the last stages of the decay. In the study of 
most any wood-destroying fungus one can almost always 
observe numerous perforations of the cell membranes in 
which the fungal hyphz no longer are present. In the course 
of the progress of the decay the hyphe branch and rebranch 
until they permeate all of the woody elements. It is not 
to be supposed that all of this increasing volume of fungal 
mycelium functions in the decay of wood but that it is 
mainly the minute, last-formed hyphe that are active in 
secreting enzymes which gradually render the woody sub- 
stance soluble and capable of absorption and translocation 
by the fungus. It is evident, from the habitual disappear- 
