THE STRUCTURE AND WORK OF THE STEM 109 



Food Storage. Many monocotyledonous trees which live for 

 long periods of time store food in large quantities in the trunk. The 

 sago palm is an example. 

 The sugar cane is a mono- 

 cotyledonous stem of great 

 commercial value because 

 of the sugar contained in 

 its sap. Over 70 pounds 

 of sugar on the average is 

 used annually by each per- 

 son in the United States. 

 Most of the cane sugar 

 grown in this country 

 comes from Louisiana and 

 Texas, although these 

 states do not begin to 

 supply the needs of this 

 country. The diagram fol- 

 lowing graphically shows 

 the sources and kinds of 

 sugars used in the United 

 States. 



Roots and Stems as 

 Food. Underground 

 stems and roots form 

 some of the most important sources of man's food supply. Our 

 commonest foods, as the potato, sweet potato, onion, carrot, parsnip, 

 turnip, and beet, are well-known examples. The sago palm is the 



Kind and Sources Sugar Consumed in United States Percentage 

 i g^gggJL^^^&^^^y^^^^ %ga^saaA^g8gggg^i 7| ^ ^ 



Cane Beet 



Palms and palmettos ; typical monocotyledo- 

 nous plants. Scene on Indian River, Florida. 



East Indies 



United States 



Cuba 



Germany Rest World 



chief support of many of the natives of Africa. Each adult tree will 

 furnish 700 pounds of sago meal, 2^ pounds being enough to support 

 a man one day. The cassava root, from which tapioca is made, is 

 one of the main supports of African natives. Sugar, from the beet 



