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UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



crosses, showing as very vigorous, characteristic trees entirely different 

 in appearance from those of the ordinary type. Such individuals have 

 all the vigor of growth and other characteristics of first-generation 

 Paradox trees. 



"With Royal hybrids the English seems much more free to cross and 

 when English and Royal trees grow near together the resulting seedlings 

 are very much mixed. We know of no large trees which can be posi- 

 tively ascribed to this cross, but have obtained numerous examples of 

 them in the nursery among the seedlings of Royal trees which stood 



FIG. 17. Young Royal hybrid walnut tree, showing foliage. 



close to English walnuts. Such individuals have all the vigor and desir- 

 able characteristics of the first cross. 



Seedlings of Paradox Trees. Paradox walnut trees of the first gener- 

 ation, that is, those of the first cross which originated directly from nuts 

 cross-pollinated by other species, are almost without exception trees of 

 unusual vigor and exceptional rapidity of growth. It 'would therefore 

 seem that seedlings from such trees, grown from the nuts which they 

 produce, would also be exceptionally vigorous trees. Such is not the 

 case, however, especially as regards the use of such seedlings as root- 

 stocks for the English walnut. These trees, in every instance which we 

 have tried or known of, do not show exceptional vigor, and English wal- 



