Dec, 1906.] A Successful Mutant of Verbena. 33 



processes of evolution can be discovered only through series of 

 pedigree cultures. The peculiar notion, that species, to be good 

 species, must have their origin in the field, or nature's garden, 

 and not in man's, has come down to us from a previous genera- 

 tion. This notion with other modes of thought, formulae, and 

 assumptions has been so diffused through scientific thought and 

 literature that it is held by many as a kind of dogma which if 

 logicallv applied would exclude experimentation entirely as a 

 factor in determining the character of evolution and speciation. 



Any mutation which is Mendelian may theoretically give rise 

 to a new race under favorable conditions. At the present time 

 one mav sometimes find two or three species according to the 

 systematist among the branches of a single tree. There is, 

 therefore, no occasion to waste words as to what is a true species 

 or elementary species, nor how great or small a variation must 

 be before it may be called a mutation. The real test should be 

 as to whether the type breeds true without special selection or 

 isolation. Recentlv the claim has been made by certain natural 

 selectionists that it is selection and segregation that makes 

 mutants breed true. But deVries' mutants and the Verbena 

 mutant have, so far as anything can be determined by field 

 observation, the quality of breeding true, created by or along 

 with the original mutation process and not by selection. Per- 

 haps if I were able to study and test some of the qualities of the 

 Verbena mutant by means of definite pedigree cultures, the 

 claim would again be made that the method employed was a 

 process of selection. Although the Verbena mutant is a decided 

 saltation, there is no reason why a similar change should not take 

 place in a given locality by a series of very small advances, the 

 saltation so to speak, continuing through a number of genera- 

 tions before again coming to a more or less fixed type. But this 

 is outside of the questions raised by the case in hand. 



The opinion has been commonly held for many years that 

 sports, in the old sense of the term, are lost by the swamping 

 effect of cross-breeding. But if there are variations which are 

 not swamped, selection becomes an unnecessary factor in the 

 origin of distinct forms; and the Verbena mutant is a case in 

 evidence of a distinct type entirely successful from the beginning. 

 This belief that sports are always swamped is, however, largely 

 based on assumption. 



Geographical isolation has, recently, also been claimed to be 

 the important factor in speciation. The statement that no two 

 closely related species or subspecies occupy the same territory 

 or even the same habitat certainly appears ill-founded to any- 

 one acquainted with the distribution of plants In many cases, 

 according to Britton's Manual, the variety has the range of the 

 type and this is true for species where the habi tat is of a uniform 



