40 LUTHER BURBANK 



although the variation in size and foliage is less 

 than in the case of the Paradox. The extraor- 

 dinary range of size, some of the second-genera- 

 tion hybrids being giants and others dwarfs, 

 has been elsewhere referred to. It will be re- 

 called that some of these second-generation hy- 

 brids grew to the height of four feet in the first 

 year, while beside them were others that grew 

 only six or eight inches and some only one and 

 one-fourth inch. The nuts from which they 

 grew had been picked from the same tree, and 

 planted the same day side by side. 



To make sure of securing trees having ex- 

 actly the traits of the original Royal, it is neces- 

 sary to grow the trees from grafts either of the 

 first-generation hybrid or a selected second-gen- 

 eration hybrid showing rapid growth. The num- 

 ber of the latter, however, is sufficient to insure 

 a reasonable proportion of good trees from any 

 lot of seed; and the Royal has been in general 

 demand as a tree to furnish stocks on which 

 the Persian walnut may be grafted, and for 

 forestry. 



It is found that on most soils a Persian wal- 

 nut grafted on roots of the Royal hybrid will 

 produce a much larger crop than if on its own 

 roots. Moreover the trees under these condi- 

 tions are relatively free from the blight. 



