LINNZEAN SPECIES 7 



on civilized men paid closer attention to tne different 

 kinds of plants, and the old herbalists discovered and 

 described a number of different sorts of roses, of butter- 

 cups, and of other plants, and distinguished each by a 

 descriptive sentence. 



As more and more species came to be described, this 

 method of designation became very cumbersome, until 

 Linnaeus, about the middle of the eighteenth century, 

 adopted the idea of a binomial nomenclature (originally 

 suggested by Bachmann), in which every species of 

 each known genus received a separate name of its own 

 to distinguish it, so that the different kinds of butter- 

 cups were now known as Ranunculus acris, R. bulbosus,. 

 R. sceleratus, and so on. 



Linnaeus himself appears to have had a very definite 

 idea of what constituted a species, and in accordance 

 with the view then current, he denned a species as 

 being a group of organisms which owed its origin to a 

 separate act of creation. From the nature of the case 

 this definition could be of little use in practice. Prac- 

 tically, then, species were defined as groups of animals 

 or plants, the members of which resembled one another 

 in definite morphological characteristics that is to 

 say, in constant features of form and structure. This 

 definition has survived the downfall of the dogma of 

 the constancy of species, and at the present day species 

 as defined by Linnaeus are found to be groups of much 

 merit both for naturalness and for convenience at 

 any rate in the case of plants. The fact that inter- 

 mediate forms and minor groups do sometimes and to 

 some extent bridge over the gap which separates a 



