THE SEEM te 
‘nettle it is not easy. A length of stem including at least 
three internodes is necessary; boiling the stem for two or 
three minutes makes it easier to remove the cortex. The 
stem should be put into a solution of aniline sulphate; the 
fibro-vascular tissue is then stained yellow, and is more easily 
traced. The cortex should be carefully removed with needles 
or scraped with a knife ; then the vascular tissue is exposed, and 
can be traced through thelength = 
of the stem and into the leaves. oe 
Fig. 20 is a transverse section 
through the internode of the stem 
of the Dead-nettle. There is no 
difficulty in recognising the eight 
bundles, three on each side of 
the two leaf-bearing sides of the 
stem, and one in the middle of 
each side of the stem which does “ne eee 
not bear leaves. It must be 1G. 20.—[NTERNopE or Dmap- 
NETTLE, TRANSVERSE SEC- 
borne in mind that the leaves of TION. (Diagrammatic. ) 
the Dead-nettle are opposite a, b, leaf-bearing sides. 
and decussate. | | 
Fig. 21 is a transverse section through the node of the stem 
2 __ of the Dead-nettle, and there, 
instead of eight bundles, six- 
teen are seen. At the node the 
leaves arise, this section there- 
fore shows the bundles of the 
leat before they have fused 
with those of the stem. To 
understand the arrangement 
thoroughly the bundles must 
be traced lengthways. In 
Fig.- 22 the cortex has been 
NETTLE, TRANSVERSE Sec. removed, and the longitudinal 
TION, (Diagrammatic. ) course of the bundles can then 
a, b, leaf-bearing sides ; ¢, cen- 
tral bundle ; 7, lateral bundles ; be traced. 
w, wing bundles, It will there be seen that 


