4 Charles E. Bcsscy 



while those that appear to be derivatives from these primitive 

 families are arranged tov^ard the end of the order. In many in- 

 stances the sequence has been worked out to the author's satis- 

 faction; in other cases, however, it has not yet been possible to 

 make such a satisfactory disposition of the families, and here no 

 doubt some considerable changes in the sequence will have to be 

 made in a later edition of this Synopsis. In the meanwhile it is 

 hoped that this prodrome may prove useful to students of sys- 

 tematic Botany, in directing their attention to the possibilities of 

 the phyletic classification of plants. 



278 



