44 NATURE TEACHING. 



tip of the same branch, will show that the 

 leaves arise exactly as on the upright growing 

 shoot and merely twist later into their final 

 position. From a careful examination of these 

 various cases it will be apparent that the parts 

 of a plant are not rigidly fixed in any particu- 

 lar way but that each can adapt itself to 

 special circumstances. 



2. Stems, like roots, often serve as store- 

 houses of food, for instance, the sugar-cane 

 stores up a large amount of sugar in its stem, 

 and similarly the sago-palm stores starch. The 

 majority of the stems which serve as store- 

 houses do not stand erect in the air as in the 

 examples already given, but grow partially or 

 entirely beneath the surface of the soil. In 

 general appearance these underground stems 

 resemble roots, indeed in some cases it is 

 difficult to distinguish them from roots. It 

 may, however, be taken as a general rule that 

 a stem whatever use it may serve always 

 bears leaves. The examination of the examples 

 given below will show us that we do not find 

 green leaves in every case, as in underground 

 stems the leaves are more commonly reduced 

 to dry, scale-like bodies. 



3. Ginger affords a good example of a 

 stem of this kind, running horizontally in the 



