144 College of Forestry 
ternut hickory the last stages of the decay were represented 
by membranous partitions of resistant wood separating the 
pockets. As seen microscopically the membranous layers of 
wood varied from one to several cells thick, and the elements - 
often were full of matted hyphe. Within the individual 
pockets practically nothing was left save for a few scattered, 
half-disintegrated vessels weakly held together by a few 
fungal hyphee. Practically all of the woody substance, as 
well as the fungal hyphe, had disappeared within the indi- 
vidual pockets (Plate XXIV, Figs. 1 and 2). In the decay 
of sugar maple wood the pocket formation was less pro- 
nounced than it was in either decayed yellow birch or bitter- 
nut hickory wood. In the sections studied the decayed wood 
was by no means reduced to the same extent as that just 
described for yellow birch and bitternut hickory, but the 
decay seemed to become completed before less of the woody 
substance was so completely destroyed. Microscopic exami- 
nation showed a reticulum of resistant wood but it was 
much less conspicuous than that observed in either decayed 
yellow birch or bitternut hickory woods. The more lignified 
cells within the center of these zones often were stuffed with 
matted hyphee as in the case of the decay of the two last- 
named woods. Within the less sharply demarked individual 
pockets considerable partially decayed material remained, 
including the multiseriate pith-rays, the vessels together with 
the cells immediately surrounding them, and the terminal 
zone of more lignified cells on the outer face of the growth 
ring (Plate XXIII, Fig. 2). It would appear, therefore, 
that the decay either does not progress so far in sugar maple 
as it does in yellow birch and bitternut hickory wood or that 
the localization of the decay into pockets is in time overcome 
before the decay becomes completed, after which the subse- 
quent decay would progress uniformly and involve the whole 
of the remaining woody substance. In the decayed chestnut 
oak wood studied the pocket formation was inconspicuous. 
The woody substance had not disintegrated quite as far as 
it had in the decayed sugar maple wood studied. Microscopic 
sections exhibited a distinct reticulum bounding the pockets. 
