X PREFACE. 



long as the limits of the orders themselves are unchanged ; 

 for the latter are the basis of the system, to which all 

 other considerations are subordinate. Such a collection 

 of orders as that here given cannot certainly be called 

 " the Natural System" of the Vegetable Kingdom, in the 

 proper sense of those words ; but it is what Botanists 

 take as a substitute for it, until some fixed principle 

 shall be discovered upon which combinations can be 

 formed subordinate to the first great classes of Vascu- 

 lares and Cellulares, of Exogenee and Endogense. It is 

 also certain, that in the actual state of Botany we are 

 more usefully employed in determining the characters of 

 natural groups by exact observation, than in speculating 

 upon points which we have not yet the means of dis- 

 cussing properly. 



In conclusion, the Author has only to add, that this Work 

 must not be viewed as an Introduction to Botany. Those 

 who would understand it must previously possess such 

 an elementary acquaintance with the science as they may 

 collect from his Outline of the First Principles of Botany, 

 or some other work in which the modern views of vegetable 

 organisation are explained. This, and the following in- 

 troductory sketch of the principal modifications of struc- 

 ture, will be found to convey as much information as is 

 absolutely required with reference to the immediate subject 

 of the Work. 



