32 Plants and their Ways in South Africa 



Do you know any ? Do they shed their leaves so that they 

 are quite bare at some time of the year ? Can you tell how 

 long leaves remain on any evergreen tree ? 



While roots are absorbing food material, leaves are taking 

 in air and combining the air and water with the dissolved 



Fig. 37. — Leiiticels on the bark of poplars. 



earthy matter into food. Air, earth, and water seem at first 

 rather unsustaining diet, but when we consider, we find that 

 people, in common with other animals, since they depend 

 altogether upon plants for food, are nourished by the same 

 materials. 



Leaf Fall. — When leaves have finished their work, the 

 food that is left in them passes down into the tree, and is 

 stored away in the roots until it is needed for the new growth 

 the following season. A layer of cork is then formed in the 

 leaf, where it joins the stem, which prevents the upward flow of 

 sap passing back into the leaf, so it withers and falls off. The 



