BULLETIN 231] 



WALNUT CULTURE IN CALIFORNIA. 



159 



much better than does the English walnut, growing vigorously under 

 extreme conditions of both sorts. 



In our experimental orchard on the state school grounds at "Whittier 

 there is a tree of the southern California species which was planted in 

 1907 along with the other trees. This tree is the first in the grove to 

 come out in the spring, and all the English walnut trees immediately 

 around it are French varieties, which do not come out for at least two 

 months after this black walnut tree is past its blooming period. In 



FIG. 16. Camulos tree; Paradox. (Photo by Prof. W. T. Clarke.) 



the farther end of the orchard to the west, some five or six hundred 

 feet away, there are, several trees of southern California English walnut 

 varieties, some of w r hich produce pollen nearly as early as does this 

 black walnut tree. This tree in the spring of 1910, when four years 

 old from the nut, set a crop of several hundred nuts, over 90 per cent of 

 which when .planted the following year produced Paradox hybrids of 

 an extremely vigorous type. In 1911 the tree produced a much larger 

 crop of nuts. It would appear in this case that the crossing with 

 English pollen, probably mostly from the Chase variety, increased the- 



