68 NATURE TEACHING. 



plants, especially those which live in very dry 

 places or near the sea, have leaves which are 

 thick and fleshy and sometimes very difficult 

 to distinguish in appearance from stems. We 

 have also seen already, when examining ginger 

 and arrowroot stems, that leaves are not always 

 green. Other examples of the various char- 

 acters which leaves can assume will be met 

 with later. 



USES OF LEAVES. 



1. Leaves are necessary for the health and 

 growth of most plants, as in them are carried 

 on the processes of breathing and the manu- 

 facture of food- material. The consideration 

 of these processes is, however, best deferred 

 until we have made ourselves acquainted with 

 the structure of leaves. We will therefore 

 first deal with their other, less important uses. 



2. The young leaves of most plants are 

 very delicate and easily damaged by exposure 

 to the sun. It is common to find these young 

 leaves protected by the older ones, as may be 

 seen in the leaf- buds of the coleus and many 

 other plants. In bananas and tannias the 

 young leaves are rolled up in the hollowed 

 leaf- stalk of an older leaf. The school garden 

 will readily furnish numerous other interesting 



