36 A TEXTBOOK OF GENERAL BOTANY 
Parenchyma. ‘The regions between the collenchyma cells and 
the central portion of the midrib are occupied by parenchyma 
cells. In Fig. 24 this parenchyma is shown as a ring of tissue, 
which in the drawing appears to be lighter colored than any 
of the tissues touch- 
ing it. This lighter 
appearance is due to 
oe BS the combination of the 
F Eth Ee be RORY Ho too oe O56 large size of the cells, 
ht Es ¥4 iy oS ELD dh bo g the thin walls, and the 
: +% Revd Ae B re: » pe Bo absence of chloroplas- 
ne tids. In structure the 
parenchyma cells are 
not specially modi- 
fied for any particu- 
lar function, but they 
perform all the gen- 
eral functions of cells 
to a limited extent. 
Parenchyma cells have 
thin walls, but on ac- 
count of their turgid- 
1 ity they strengthen 
Fig. 28. Cross section of the thin part of a leaf the midrib. That a 
(/xora), showing the connection of the chloren- considerable part of 
chyma with a vein the stiffness of most 
&, 
5% 
oO 

The vein is seen in the center as a compact group leaves is due to the 
of cells. (x 215) water in their cells 
can be readily dem- 
onstrated by means of leaves which have been severed from a 
plant. Such leaves continue to lose water by transpiration. As 
this water is not replaced, the cells of the leaf will contain less 
and less water and will lose their turgidity. We see the result 
when the leaf wilts and becomes soft. 
Conducting system. The tissues composing the conducting 
system are situated near or at the center of the midrib. This 
