xv INTRODUCTION. 



any means so extensive as seriously to in- 

 jure the authority of these Lists. There 

 is another cause which troubles the en- 

 quiry more than this does. I mean a 

 certain levity of transit from plant to plant, 

 which happily is not exhibited everywhere, 

 but there certainly is a large circumam- 

 bient zone of what may be called volatile 

 names. These flitted from one plant to 

 another, according to some agreement 

 either of look or of quality, by which 

 plants were associated, sometimes fantas- 

 tically enough. The existence of such a 

 laxity must not however blind us to the 

 proofs of a better knowledge, however 

 partial it may have been. And on the 

 whole the evidences of this better know- 

 ledge will be found by tracing back from 

 below, rather than by verifications based 

 upon ancient texts. 



The endeavour of this section will be 

 to sift out the certain from the uncertain, 

 and not so much to identify all the names, 

 as to make a study of the methods whereby 

 identification may be approached. If we 

 can discover some evidential tracks which, 



