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Fics. 2, 2a.—Fig. 2, Aloe ferox, transverse 
section of part of stem: s, secondary cortex; 
pc, primary cortex; r, outer region of cells 
cut off by bi 1 contain 
ium; x*, region of secondary bundles; », 
primary polystelic region. 
BOTANICAL GAZETTE 
[NOVEMBER 
was 2 cm. and the cortex 
4 mm. in width; so that the 
central region, nearly 10 cm. 
in diameter and consisting of 
primary structures, gave the 
whole section somewhat the 
appearance of a large pith 
surrounded by a narrow zone 
of wood and a scanty cortex. 
The general topography of 
a small portion of a trans- 
verse section, natural size, is 
shown in fig. 2a. In the pri- 
mary region (p) the bundles 
are large and scattered, as in 
a cornstalk; while in the zone 
of secondary growth («?) the 
vascular bundles are so reg- 
ularly arranged, that to the 
naked eye they form a pat- 
tern like the chasing on a 
watch. The cambium (c), 
which is giving rise to sec- 
ondary bundles, the second- 
ary cortex (s), and some of 
the primary cortex between 
these two zones of secondary 
growth, are also visible to the 
naked eye. 
The phellogen, with the 
secondary cortex produced by 
it, the inner cambium with its 
derivatives, and also the pri- 
mary cortex (pc) between the 
two secondary products, are 
shown in fig. 2. The walls 
of the secondary cortex are 
