74 SOUTH AFRICAN BOTANY 
them. This tissue is known as the Sponcy PaREN- 
cHYMA. The palisade cells contain much more chloro- 
phyll than the spongy tissue, and are especially adapted 
for the work of assimilation. The spongy parenchyma, 
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Fic. 44.—Leaf of Privet, 
KE, Epidermis of upper, E, of under surface. ©. Cuticle. P. Pali- 
sade cells. V. Vascular bundle enclosed in its sheath. 8. Stoma. 
G. Guard cell. Gi. gland. (From Farmer’s ‘“ Practical Intro- 
duction to the Study of Botany ”’.) 
on the other hand, is especially adapted for the inter- 
change of gases. 
The lower ends of groups of palisade cells converge 
on one cell of the spongy tissue which acts as a CoLLECT- 
ING CELL and passes on the products of assimilation 
to the bundle. 
The whole of the tissue between the upper and lower 
epidermis is called the Mrsopuytu. Between the pali- 
