32 



FOOD RESERVOIRS 



seed to grow until it establishes itself in the earth. The flow- 

 ers of early-blooming trees are developed mostly from the 

 nourishment stored in the twigs, not from the materials 



taken in at the time by the roots, nor from food being made 

 by the newly forming leaves. This can be demonstrated 

 by bringing branches of peach, apple, and other early- 

 blooming plants into the house in the winter and keeping 

 them in water; they will bloom and sometimes even make 

 leaves. Study Fig. 46. 



78. Kinds of Storage-organs. — Short and 

 much thickened or swollen parts of roots or 

 stems are known as tubers. These may be 

 stem-tubers, as the potato, or root-tubers, as 

 the sweet potato (45). Most tubers are sub- 

 terranean. 



79. Many tubers are stem at the top and 

 root in the remaining part: these are called 

 crown-tubers, because the upper part comes 

 to the surface of the ground, or is a crown. 

 Leaves and stems arise from the upper part. 



