OTHER USEFUL PLANTS 89 



grown here and there in the field to fertilize the 

 others, the cultivators feeling that the seed which 

 would not otherwise be produced has at least the 

 value of adding weight to the flower heads, and 

 probably it adds lupulin also. 



The hop has been grown from prehistoric 

 times, and the exact country of its origin is 

 not known, although it is found growing wild in 

 Colorado and New Mexico in the mountains. 



It goes without saying that different strains of 

 hop vines differ in productivity, and in the 

 amount of lupulin that their flowers secrete, and 

 in the quality of the product. Certain Bavarian 

 hops have lupulin of peculiarly fine flavor, but 

 these are all less productive than the hops grown 



in America. 



THE SUGAR BEET 



The possibilities of stimulating a plant to out- 

 do itself in the production of its characteristic 

 carbon compounds are well illustrated by the 

 story of the sugar beet. 



It was not much over a half century ago that 

 the merits of this vegetable as a producer of 

 sugar began to be seriously considered. 



The fact that sugar cane grows only in warm 

 climates, and that here is a hardy plant that may 

 be grown anywhere within the temperate zone, 

 stimulated the older Vilmorin brothers of Paris, 



