Lena 
300 BOTANICAL GAZETTE [NOVEMBER 
Fics. 11-13.—Aloe ferox: fig. 11, trans- 
Vv secondary bundle; fig. 12 
longitudinal radial section; fig. 13, longitu- 
dinal tangential section; X 100. 
rse section of 
by 
oxalate; but the cell walls 
thicken very little and retain 
the cellulose reaction (fig. 2 7.) 
The cells formed centri- 
petally from the cambium 
give rise to the secondary 
woody structures which show 
the growth rings. The devel- 
opment of the bundle was not 
studied very thoroughly in 
Aloe ferox, but the early 
stages are about the same as 
in A. pleuridens. As seen in 
transverse section, a cell of 
the row produced by the cam- 
bium divides, the two result- 
ing cells divide, and the 
process continues until forty 
or fifty cells are formed (figs. 
7-10). Differentiation of the 
young cells of the vascular 
strand begins to take place 
before the full number of cells 
has been reached. These 
bundles are completely am- 
phivasal and there is no 
sheath of thick-walled cells. 
The phloem is scanty and 
companion cells are rare. 
There is no degeneration or 
clogging of the lumen in the 
secondary bundles, and there 
is no meristematic activity in 
any of the surrounding cells, 
like that which characterizes 
many of the bundles of the 
primary cylinder. Since the 
