CHAPTER XXI 



ORIGIN OF FARM AND GARDEN VEGETABLES AND 

 MISCELLANEOUS PLANTS 



The potato • The sweet potato • Miscellaneous tubers • Edible roots • The 

 nion • The beet • Manioc, or mandioca • The turnip • Miscellaneous roots • 

 \'egetables cultivated for their foliage • Cabbage • Celery • Lettuce • Aspara- 

 gus • Plants cultivated for beverage • Coffee • Tea • Matd • Plants grown 

 for sedative effect • The poppy • Coca • The betel • Tobacco • Fiber plants • 

 Cotton • Flax • Hemp • Ornamental plants • Weeds 



Many plants have a habit of sending out not only the upright 

 stems that bear leaves, but also others that run along just above 

 >r just beneath the surface of the ground, and, by branching or 

 >ending out roots at the joints here and there, are able to prop- 

 agate themselves without the help of seeds. Strawberries do 

 this with " runners" above the ground. Quack grass and Canada 

 thistle do the same, except that the stems run just below the sur- 

 face, a habit which makes these two weeds peculiarly difficult to 

 radicate. Blue grass has the same habit, but, being valuable in- 

 tead of worthless, we count the custom a virtue and not a vice. 



In a few plants these underground stems greatly thicken, and 

 these thickened stems, called tubers, are favorite foods, generally 

 IS a source of starch. 



The potato (Solanum tuberosum). The most common and the 

 most valuable of all plants of this order is the ordinary Irish 

 IK)tato. Its name " Irish " is a misnomer,^ as it is truly an Ameri- 

 can product, its wild progenitor still being common along the 

 oast of Chile and in the higher elevations to the northward. 

 Several closely related species abound in the highlands of South 

 md Central America as far north as Mexico, and a not distantly 



* Bestowed from the fact that the cessation of the periodic famine in Ireland 

 dates from the introduction of the potato. 



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