98 USE OF THE FLORA [CH. VI 



the study of the Flora. I have dealt with this section of 

 the subject less in detail, because our best Floras give so 

 much information that it seemed undesirable to do more 

 than attempt to guide the reader in the recognition of 

 the genera and principal species by means of external 

 features easily observed by anyone with a little care. 

 The detailed and critical examination of species, varieties 

 and rare forms should always be done with reference to a 

 complete Flora. 



