BOTANICAL ANALYSIS 221 



older in time, and therefore more constant and less inclined to vary, 

 while those characterizing the lesser groups are more recent in their 

 origin, and much inclined to vary in different individuals. They are, 

 therefore, less trustworthy and have to be considered in connection 

 with others. It is for this reason that the most frequent differences of 

 opinion concerning classification among botanists relate to genera, 

 species and varieties. 



