SPECIES AND VARIETIES 



Are varieties incipient species, or is there any fundamental 

 difference between species and varieties? A definition of the 

 term species must cover what systematists have been calling 

 by that name and it is clearly inadmissible to use an old term 

 for a new conception, especially if to do this we, have to limit 

 the use of the term to a restricted group, a part of all. Our defi- 

 nition of species must cover such species as are known to be 

 variable. Constancy as such, trueness to type, is clearly not 

 essential. Lotsy has tried to give a definition of species by re- 

 stricting this name for those groups of organisms, which are 

 wholly pure for one genotype. We know that such species exist. 

 Most of the populations of autogamous plants can be said to 

 consist of a number of pure species, pure lines, and a few impure 

 individuals. But to restrict the use of the term species for 

 this special kind of species is as inadmissible as the restriction 

 of the term dog to coach-dogs to admit of the simple statement 

 that dogs are white, spotted all over with black dots. Such a 

 description will never be true of that group of animals which 

 are called dogs by everybody else, and Lotsy 's definition does 

 not fit the majority of groups called species by systematic zoo- 

 logists and botanists. 



Nevertheless, species are strangely pure, and if a species does 

 not necessarily consist of geno-typically identical individuals, 

 the usual procedure, the description of a typical specimen as 

 the specific type is assuredly founded on the observation,that 

 an enormous majority of the plants or animals grouped under 

 the name conform to the description. It is the current view 

 among systematists that a species is stable, that the individ- 

 uals belonging to it which are somewhat different from the 



