CHAPTER SEVENTEEN 
GARDEN PLANTS GROWN FOR THEIR STEMS 
Leaves for relishes!. But for solid support, let us have the stems. 
Nevin WoopsipE 
In the United States, Irish potatoes, the Jerusalem 
artichoke, kohl-rabi, and asparagus are the only impor- 
tant garden vegetables that are grown for their stems. 
These four plants belong to widely different families of 
flowering plants, and are very different in their cultural 
needs. 
THE IRISH POTATO 
The underground tubers, or thick, fleshy stems, of the 
potato have recently become a most important food 
for man. The plant is a native of America, but it is 
now cultivated over practically all the cooler parts of the 
world and also in the mountains of the tropics. More 
tons of potatoes than of either wheat or rice are now used 
each year for human food; so the potato is one of the 
leading food plants of the world. 
In general, potatoes are a field rather than a garden 
crop. On the farm there is every advantage in growing 
them in fields where rotation of crops is the rule. The 
villager and others who own at least a half an acre or 
more of land may find it profitable to raise potatoes, 
especially the early sorts which mature at the time po- 
‘tatoes command the highest prices. In the small garden, 
where intensive methods are necessary and a crop must 
be judged by the returns for the space it occupies, the 
potato is not as profitable as some other crops. Another 
reason for buying potatoes, rather than raising them in a 
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