BULLETIN 231] WALNUT CULTURE IN CALIFORNIA. 167 



old mill building on the ranch a very large eastern black walnut tree 

 that was cut down about 1883 or '84 and had a diameter of about four 

 feet. This tree was, I believe, bearing when Colonel Kewen bought the 

 property from a Mrs. Holt. The other black walnut trees were raised 

 from seed from this original tree. ' ' 



In the canons back of this ranch, and at no great distance from the 

 mill, there is still to be found a considerable number of native trees of 

 the southern California type, so that presumably such trees were orig- 

 inally quite abundant here. It is, therefore, most reasonable to suppose 

 that the various trees of this El Molino type are Royal hybrids, resulting 

 from a cross between the old nigra tree by the mill and these wild 

 southern California trees. It is remarkable, however 2 that all the seed- 

 lings grown from the nuts of this tree should have been hybrids, which 

 appears to be the case. There are probably at least fifty of these seed- 

 lings represented by the present large trees on the ranch and a consid- 

 erable number more scattered about the surrounding country, and not 

 one of these trees can in any possibility be considered a true nigra. It 

 may be that in planting these trees the largest specimens in the nursery 

 were picked out and in this way nothing but hybrids were chosen. Such 

 a case is indeed quite probable, as the straight nigra seedlings grow only 

 a few inches the first year, while the hybrid trees among them may be 

 several feet in height. Naturally these largest trees would be chosen for 

 permanent planting. 



Seedlings of Royal Hybrids. The seedlings originating from first- 

 generation Royal trees, of either the northern or southern California 

 type, are in general much more vigorous and retain the qualities of their 

 parents to a much greater extent than in the case with seedlings of 

 Paradox trees. In the second generation, however, that is, trees twice 

 removed from the original cross, the exceptional vigor is mostly lost and 

 the seedlings become no better than or even inferior to those of the 

 original species. In other words, the Royal hybrid seems on the average 

 to retain its quality of exceptional vigor of growth one generation longer 

 than does the Paradox. Various individual Royal trees, however, vary 

 greatly in their ability to impart their characteristics to their progeny. 

 Only a very few of them give seedlings which show uniformly a large 

 percentage of trees as good as the parent. In the majority of cases the 

 seedlings vary greatly and are not at all uniform. Almost always, 

 however, the rule above stated is maintained that the seedlings of first- 

 generation trees are more vigorous than those of the second generation, 

 even though the parent trees may appear equally vigorous. This is an 

 important fact in obtaining seed for nursery planting as a rootstock for 

 the English walnut. In fact, it should be clearly understood that while 

 Royal and Paradox hybrid walnut trees are quite common in the State, 



