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 
Theacew, 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. 
