BULLETIN 231] WALNUT CULTURE IN CALIFORNIA. 147 



the latter species has been held to include, at least as a variety, the 

 southern California type, while Juglans major has frequently been con- 

 sidered a variety of rupestris. The general understanding of rupestris 

 has been that it is a decidedly dwarf, shrubby type with very small 

 nuts, while major has been considered a larger and more erect form. 

 According to Britton, Juglans major is the species indigenous to Ari- 

 zona, particularly the western portion, while the range of rupestris is 

 found further eastward in New Mexico and Texas. We have not 

 studied this subject to any extent from a botanical standpoint, but in 

 connection with our investigations on rootstocks for the English walnut 

 we have received and planted nuts from all the states just mentioned, 

 and have also through correspondence gathered considerable informa- 

 tion concerning the native black walnuts of these states. From such 

 information, together with a study of the nuts which we have received 

 and the trees grown therefrom, we are convinced on one point, namely 

 that Juglans major of western Arizona and Juglans rupestris of New 

 Mexico and Texas are quite distinct from one another and also distinct 

 from either of the California types. It is true that all four of these 

 forms run more or less into one another, and the question as to whether 

 the differences between them are of varietal or specific rank does not 

 lie within the province of the present work. It is certain, however, 

 that in the nursery the four forms are very distinct and decidedly 

 different from one another. From our observations thus far it would 

 appear that there is as much similarity between Juglans major of Ari- 

 zona and Juglans hindsii of northern California as between any other 

 two of the four types. Our observations in this respect, however, extend 

 only to the general form and appearance of the old trees, seedlings, and 

 nuts. 



NATIVE WALNUTS OF ARIZONA. 



Black walnut trees of an evidently indigenous nature are found 

 growing in various portions of Arizona. The Arizona species was 

 formerly classified as Juglans rupestris, with a variety or second species 

 called Juglans major, the latter being supposedly a more erect and 

 tree-like type than the true rupestris. Professor J. J. Thornber of the 

 University of Arizona writes as follows: . 



"We had supposed that Juglans rupestris was our common walnut 

 here and had classified it as such. Last year, however, I came to the 

 conclusion that our species, at least a considerable amount of' it,' is 

 Juglans major. This is our common walnut that grows in southern 

 Arizona, and it may be the only species. Juglans rupestris, as I under- 

 stand it, grows in Texas, though of course it may get as far as Arizona. ' ' 

 Again, "I am sending you under separate cover two quarts of nuts of 



