Species and Varieties

Abstract

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 definition 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 restricting 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.