
THE ROOT 65 
CHAPTER VIII 
THE ROOT 
| structure IF seeds of Maize are allowed to germinate in 
of Apex. ypoist air, or if a Hyacinth bulb is grown in water, 
the tips of roots can be examined. It will be seen that each © 
root is covered with a little shield, called the root-cap. ‘Then, 
if a section is made 
longitudinally through 
the apex, the tissues of 
which it consists can 
be examined under the 
microscope. It will be 
at once evident that the 
cells of which the root- 
cap is composed are fully 
grown and differentiated 
to form a: protecting 
tissue for the root; they | | 
are much larger than 
the adjoining cells, and 
are not giving rise to 
new cells. Within the 
root-cap the cells are 
small, thin-walled, and 
very similar to those 
already described at the 
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Fig. 34. —ApEx oF Root, MEDIAN LONGI- 
TUDINAL. (High power, diagram- 
matic. ) 
7.c, root cap; g.p, growing point; d, 
dermatogen ; pi, plerome ; pb, periblem. 
apex of the stem. These cells are arranged in longitudinal 
rows, and converge just behind the apex ; this is the growing 
point. It consists of meristematic tissue, which gives rise on 
one side to the root, on the other to the root-cap. The meri- 
stematic cells show differentiation into three tissues : 

