226 LUTHER BURBANK 



Mexico, California, the Mississippi Valley, and 

 nearly as far north as Hudson's Bay. 



I have done a good deal of crossing and selec- 

 tion among the seedlings to increase the grace of 

 the plants and delicacy of bloom, and to make the 

 silvery, graceful leaves of one species replace the 

 rough, coarse leaves of another. 



There is no great difficulty in hybridizing the 

 various species, especially if care is taken to 

 wash away the pollen by the method described 

 in the chapter on artificial pollination. But 

 there is great difficulty in fixing a variety 

 after it is formed. The hybrids tend to take 

 on many forms, their variability in the second 

 generation suggesting that of the gourd 

 family. 



Of course this difficulty does not apply in the 

 case of the artichoke, as this is propagated only 

 from tubers, just as the potato is propagated. 

 So any improved variety developed is fixed from 

 the outset. There has not hitherto been enough 

 demand for the plant in this country to stimulate 

 the plant developer to work with it. But it is 

 probable in the near future there will be renewed 

 interest in certain less common garden vegeta- 

 bles, comparable to that shown in recent years in 

 the development of the orchard fruits, and in that 

 case the Jerusalem artichoke is almost certain to 



