LETTER XLIX. 



A SYSTEMATIC ARRANGEMENT OF PLANTS, ACCORDING 

 TO THEIR NATURAL RELATIONS, OR SUMS OF RE- 

 SEMBLANCE. 



All that you have learned of the vegetable king- 

 dom has been designedly desultory and unmethodicah 

 My object has been not to engage your attention bv 

 explaining to you any particular system, but rather to 

 store your mind with the facts upon which all systems 

 must rest. 



But as all systems of arrangement must be unintel- 

 ligible to those unacquainted with details, so on the 

 other hand must the most copious and well considered 

 details be deprived of a great part of their value, if 

 they are not so arranged as to illustrate and explain 

 each other, as well as to be found whenever the 

 memory seeks for them. 



I shall, therefore, without further preface, give you 

 in this letter a sketch of an arrangement of the com- 

 moner Natural Orders of plants, according to their 

 resemblances ; leaving you to make out the final dis- 

 tinctions between them by such means as vou now 

 possess ; premising only, that throughout the whole of 

 this compendium I have used the word trihe^ as an 

 equivalent for what is more generally termed a natural 

 order. 



