TgI0] BAILEY—TRAUMATIC OAK WOODS 377 
to embryonic or seedling stages. We should accordingly expect to 
find in wounded oak wood a reversion to primitive ray structure. 
That this reversion does occur has been shown conclusively by 
the examination of numerous areas of wounded oak wood. In 
fact, in all cases a complete series of transitional stages in the 
development of compound rays occurred, resembling the series 
of steps found by Eames in the development of seedling plants. 
The wood formed immediately after wounding possesses char- 
acteristically only uniseriate rays. In following layers aggrega- 
tions of the rays develop, with subsequent enlargement of the uni- 
seriate rays, and their subsequent fusion into homogeneous masses 
or compound rays. During this compounding process, fibers and 
wood parenchyma included in the fusing mass are transformed 
into ray parenchyma. 
In all cases, in securing material, burls and distorted tissues ~ 
were carefully avoided and saa traumatic tissue 
selected. 
In fig. 1 may be seen a tangential section of the normal adult 
wood of Quercus nigra L. The so-called primary and secondary 
tays are characteristically developed; the former consists of a 
homogeneous mass of ray parenchyma. In contrast to this the 
traumatic wood of the same species may be seen in fig. 2. The 
large ray is seen to consist of a compounding mass of smaller rays. 
Figs. 3 and 4 illustrate the normal and traumatic condition in 
Quercus virginiana Mill., the important live oak of the southern ~ 
United States. As may be seen, in this species the normal adult 
wood is characterized by an imperfectly compounded ray. Numer- 
ous included fibers and wood parenchyma cells, evidences of fusion, 
are usually present. Fig. 4 illustrates the reversion of the wood 
in the vicinity of the wound to the non-aggregated uniseriate 
condition. 
In figs. 5 and 6 are shown sections of the normal and the trau- 
matic wood of Quercus densiflora Hook. and Arn., a live oak whose 
normal adult wood is characterized by large rays in which the pro- 
cess of compounding is clearly shown. The wounded wood of 
species reverts to a more primitive type of aioe ey as 
may be seen in fig, 6. 
