SOME USEFUL PLANTS 333 



the summer is short, cool, and moist, so that wheat or 

 Indian corn would not mature. Many varieties have been 

 produced by selection from seedling plants, and under the 

 influence of long cultivation the size of the tubers has 

 greatly increased and the tendency to produce seed in 

 the berries (commonly known as "potato balls") has 

 diminished. 



409. Tea. — Tea cannot properly be called a food, since 

 if drunk without cream or sugar it supplies only traces of 

 nourishment. It is, rather, a mild stimulant, but is so com- 

 monly taken with food that it may be mentioned with food 

 products. The tea-plant is a shrub belonging to the family 

 Theacece, to which the familiar camellia of the greenhouses 

 also belongs. It is thought to occur in a wild state in 

 eastern India and has for ages been cultivated in India, 

 China, and Japan. The tea-leaves are picked several times 

 during the season and dried for packing and shipment. 

 The various colors and grades of tea depend mainly on the 

 maturity of the leaves and the amount of fermentation 

 which they are allowed to undergo before drying. 



410. Starch and Sugar. — Starch can be obtained on a 

 large scale from any of the grains by grinding them into 

 flour or meal, treating this with sulphurous acid or alkaline 

 solutions in order to get rid of the sticky proteid material 

 which holds the starch grains together, and then washing 

 the starch out clean from the bran and other impurities 

 with which it is mixed. Corn-starch, for use as food, is 

 extensively manufactured in this country. 



Sago is the purified starchy pith of sago-palms, small 

 trees found in Siam and the Malayan Islands. It is also 

 made from palm-like plants (cycads), natives of the West 

 Indies. 



