PARTS USED AS FOOD 



325 



until it crystallizes when cold. More than 16,000 tons of maple 

 sugar is obtained every spring, Vermont producing about 40 per cent 

 of the total output. The sago palm is another stem which supports 

 the life of many natives in Africa. Another stem, growing under- 

 ground, forms one of man's staple articles of diet ; this is the potato. 



Roots as Food. — Roots which store food for plants form an 

 important part of man's vegetable diet. Beets, radishes, carrots, 

 parsnips, sweet potatoes, and many others might be mentioned. 



The following table shows the proportion of nutrients in some of 

 the more common roots and stems : 



Potato . . 



Carrot . . 



Parsnip . . 



Turnip . . 



Onion , . 

 Sweet potato 



Beet . . . 



Water 



75 



89 



81 



92.8 



91 



74 



82.2 



Proteins 



1.2 

 0.5 

 1.2 

 0.5 

 1.5 

 1.5 

 0.4 



Carbo- 

 hydrates 



18 



5 



8.7 



4. 



4.8 

 20.2 

 13.4 



Fat 



0.3 

 0.2 

 1.5 

 0.1 

 0.2 

 0.1 

 0.1 



Mineral, 

 Matter 



1.0 

 1.0 

 1.0 

 0.8 

 0.5 

 11.5 

 0.9 



Fruits and Seeds as Foods. — Our cereal crops, corn, wheat, 

 etc., have played a very important part in the civilization of man 



Wheat Nuts Pear 



Seeds and fruits used for food. 



Melon 



and are now of so much importance to him as food products that 

 bread made from wheat flour has been called the " staff of life." 

 Our grains are the cultivated progeny of wild grasses. Domesti- 



H. NEW CIV. BIOL. 22 



