ini3] BabcocJc: New Form of Juglans 11 



are also sufficiently distinct from /. californica so that hybrid 

 offspring of the F^ generation wonld hardly resemble our new 

 form. Exceptions to this would be J. ntpestris and J. major, 

 the Texan and Arizonan species, which resemble -/. californica 

 rather closely, and on this account the possibility of our new form 

 being an Fj hybrid between either of these species and /. califor- 

 nica is even less likely. Hence, while it is very desirable that a 

 systematic study of hybridization among all species of Juglans 

 should be made, because of its botanical, genetic and horticultural 

 interest, the writer does not consider it likely that the new form 

 is a hybrid between /. californica and any other known member 

 of the genus. By analogy we may eliminate all other members of 

 the family Jugiandaceae from similar participation in the origin 

 of the new form. 



Turning next to the three hypotheses which serve as a basis 

 for the investigation now in progress, it would seem that sufficient 

 work along any one of these lines might lead to a solution of the 

 problem. They will be discussed in the order in which they 

 were originally taken up by the writer. They are as follows : 



(1) The new form may be a natural hybrid between Juglans 

 californica Wats., and Quercus agri folia Nee, or some other oak. 



(2) The new form may originate in certain teratological 

 flowers that have been discovered on certain Juglans californica 

 trees. 



(3) The new form may be the result of mutations in certain 

 male or female flowers (or both) of certain Juglans californica 

 trees. 



First Hypothesis 



Let us consider first the possibility of origin through hybrid- 

 ization between walnut and oak. The original trees were first 

 shown to the writer as "crosses between a walnut and an oak." 

 They were briefly described by him under the title ' ' The Walnut- 

 Oak Hybrids," in Jepson's The Silva of California (pp. 50-54). 

 In 1907, N. B. Pierce verbally expressed to the writer his opinion 

 that the new form is a hybrid. Since the conception of hybrid 

 origin was entertained by various persons, it seemed wise to 

 investigate the possibility, not only of the occurrence of natural 



