34 Elementary Species 



living beings, the genera were then accepted as 

 the created forms. They were therefore re- • 

 garded as the real existing types, and it was 

 generally surmised that species and varieties 

 owed their origin to subsequent changes under 

 the influence of external conditions. Even Lin- 

 naeus agreed with this view in his first treatises 

 and in his '^Philosophical Botany" he still kept 

 to the idea that all genera had been created at 

 once with the beginning of life. 



Afterwards Linnaeus changed his opinion on 

 this important point, and adopted species as the 

 units of the svstem. He declared them to be 

 the created forms, and by this decree, at once re- 

 duced the genera to the rank of artificial groups. 

 Linnaeus was well aware that this conception 

 was wholly arbitrary, and that even the species 

 are not real indivisible entities. But he sim- 

 ply forbade the study of lesser subdivisions. 

 At his time he was quite justified in doing so, 

 because the first task of the systematic botanists 

 was the clearing up of the chaos of forms and 

 the bringing of them into connection with their 

 real allies. 



Linnaeus himself designated the subdivisions 

 of the species as varieties, but in doing so he 

 followed two clearly distinct principles. In 

 some cases his species were real plants, and the 

 varieties seemed to be derived from them by 



