454 
BOTANICAL GAZETTE 
[DECEMBER 
are continuous with the vascular tissue of the central cylinder of the 
parent stem. 
Less frequently, the new shoots arise from the peripheral part of 
the wounded surface of the cortex. Both of 
these regions of origin may be used in the same 
Fic. 1.—Decapi- 
tated stem showing one 
shoot eae from the 
an 
wounded surface. X i. 
stem, as illustrated by jig. 1. 
In the case just 
referred to, a distinct group of vascular strands 
was traced from each shoot to the vascular tis- 
sues of the central cylinder. 
In certain other cases no 
vascular connection was 
found, due probably to the 
fact that the shoots were 
younger and _ undifferenti- 
ated. 
In a few cases the new 
structure stands directly 
over the central cylinder, as 
illustrated by fig. 2 and 
observed also in much older 
plants. In such cases, a 
series of vertical sections 
shows that the vascular tis- 
sues of the central cylinder 
converge to form a dome- 
shaped cap underneath the 
restored part (fig. 3), that 
is, the whole cut end of the 
central cylinder regenerates, 
in the strict sense, the lost 
part being thus restored. 
In all other cases there is 
no such restoration, but the 
production of entirely dis- 
tinct and complete struct- 
ures upon the old stem. 
Just what conditions deter- 
Fic. 2.—Young 
plant which was de- 
capitated at x and 
has produced a new 
xX E.- 
