12 



BIOCHEMICAL SYSTEMATICS 



Lewis (1957), in a brief and excellent paper dealing with the 

 relation of genetics and cytology to taxonomy, has stated. 



Highly interfertile geographical races of a species may be genetically 

 far more different and phylogenetically much more distant than 

 morphologically comparable but, intersterile populations. . . . Con- 

 sequently, we should not attempt to reflect in our formal taxonomy 

 evidence of discontinuity in the genetic system unaccompanied by cor- 

 responding genetic differentiation. 



Unfortunately too few of the early experimental workers 

 recognized the limitations of their approaches, and, instead of accept- 

 ing a modicum of rationale in the classical approaches, they were 

 often overanxious to submerge or erect a species on the basis of rather 

 limited or questionable cytogenetical data. 



The most widely used series of experimental categories are 

 the ecotype, ecospecies, and cenospecies which are based on an 



Table 2-1. Analytical key to the experimental categories. (After Clausen, 1951.) 



