46 TRELEASE— NAMING AMERICAN HYBRID OAKS. 



pears to be an expression of parentage, which may be supported by 

 morphological characters when its individual representatives meet 

 this test of mutual resemblance and difference from other named 

 assemblages, but which falls to the ground when they differ so 

 much among themselves as to make a diagnostic description impos- 

 sible. This is the case frequently, and the now commonly known 

 Mendelian laws of segregation prepare one for the expectation that 

 in some cases, at least, purely dominant and recessive seedlings of a 

 known hybrid will be no longer other than reversions to one or 

 other parent form if raised from self-fertilized seeds. 



Obviously the application of binomials to hybrids is in a different 

 category from the use of such names for species or varieties : it is 

 not a matter of taxonomy, the stability of which is generally recog- 

 nized as dependent upon a morphological basis : but a phase of 

 nomenclature, a means to the end of convenient reference to the 

 various kinds of things. There is so much to be said in its favor 

 that botanists are coming to employ it generally. A special diffi- 

 culty and source of confusion inherent in the designation of hybrids 

 under any method lies in the fact that their parentage is more com- 

 monly assumed from their characters or inferred from circum- 

 stantial evidence than actually known. Whatever the method, 

 synonymy must grow with every mistake made in this respect : but 

 the remedy for this lies with those who are responsible for report- 

 ing the parentage of supposed hybrids, as, elsewhere, it lies with 

 those who are responsible for segregating species or other formal 

 groups. 



Such a case as that of Bartram's oak, X Qucrcus JieterophvUa, 

 presents an interesting aspect of the question. This was named by 

 Michaux as though it were an ordinary species. Subsequent 

 botanists have regarded it as a cross between Q. Phellos and 0. 

 velutina. The behavior of seedlings from trees taken to be repre- 

 sentative of hctcrophylla has led to the conclusion that these were a 

 cross between Q. Phellos and Q. rubra. On this evidence, thev 

 have been given by Schneider the binomial X Q- Hollickii. If the 

 ])urpose were to name the idea of a possible cross, this would obvi- 

 ously be necessary, since the idea of the cross l)etween 0. Phellos 

 and 0. velutina would have been called X Q- heteropJiylla. As a 



