540 
ALBAN STEWART 
The first rays to appear in the outermost sections of this series 
are narrow for the most part, usually 1-4 cells wide. There are 
occasional rays, however, which are somewhat wider but none so wide 
as those which occur in sections taken farther in. A little deeper in 
the gall wood many of the rays broaden and occasionally there is a 
very wide one in which there are inclusions of fibers. Some of the 
ray combinations in this region are quite similar to the traumatic 
ray of Quercus nigra figured by Bailey (/. c). Each succeeding group 
of a few sections towards the interior of the gall shows a broader zone 
of wood around the larval chamber. With the increase in the amount 
of wood, many of the rays also increase in width until they reach the 
size shown in fig. 8. Some of these rays have inclusions of fibers as is 
shown in the figure, while others are practically free from such. 
Uniseriate rays also occur here among the fibers, etc., which lie 
between the broad rays. 
By examination of sections still deeper in the gall from those shown 
in fig. 8, a condition is finally reached in which the rays are practically 
all uniseriate. This condition is shown in fig. 9, which was taken from 
a part of a section corresponding closely in position with that shown 
in fig. 8. It is further evident that the section shown in fig. 9, was of 
gall wood and not of normal wood, which occurs a short distance 
inside, because there is a parenchymatous area to the right, not shown 
in the photograph, which was located near the base of the larval 
chamber. It is similar in structure to the part shown in fig. 3 which 
was taken from near the base of the larval chamber of this same gall. 
The section from which fig. 9 was taken also includes some of the stem 
just below the gall, a portion of which is shown in fig. 11. The 
structure of the wood is nearly normal in this portion and it is interest- 
ing to follow the broad rays from the part of the section shown in 
this figure, to the part shown in fig. 9, as they gradually break up 
into smaller ones by fiber inclusions as the section through the gall 
is approached. 
We have here a rather striking correlation between the effects 
produced by the gall stimulus and those which come about after wound- 
ing, as the results are very much the same in each case. There is 
this difference, however, that after the formation of the broad rays, 
they may break up or be replaced by narrower ones farther out in the 
gall. If such a condition exists in traumatic oak wood it is not 
mentioned by Bailey. The reversion to a supposedly primitive ray 
structure in each instance is rather striking. 
