DICOTYLEDONOUS PLAIvTTS 



383 



The Jerusalem artichoke (Helianthus tuberosus Linn.) was 

 first mentioned as a food plant in 1616. Its early history isi not 

 well known, but it probably came from the northern part of the 

 United States or Canada. 



Lettuce (Lactvxa scouriola, var. sativu-) is a well-known salad 

 plant which was cultivated by the ancient Greeks and Eomans, 



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VALUE OF ALL CROP'' 



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 P 



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Fig. 225. — Distribution of crop production in U. S. 



but its early history is not known. It probably originated in 

 so'utheastem Asia. 



The chicory {Cicliorium intyhus Linn.) is cultivated for 

 salad, as a vegetable, and for the roots, which are mixed with 

 coffee. Its early history is obscure, but it probably originated in 

 eastern Europe and western Asia. 



The endive (C endivia Linn.), which is also grown for salad, 

 probably originated in the same part of the world. 



