xivi PREFACE. 



tvhat period the order was first noticed, and also in what works he is to 

 look for further information upon it. To this succeeds the Diagnosis, 

 which comprehends the distinctive characters of the order reduced to their 

 briefest form, and its most remarkable features, without reference to excep- 

 tions. The latter are adverted to in what are called Anomalies. Then 

 follows the Essential Character ; a brief description of the order, in 

 all its most important particulars. This is succeeded by a paragraph 

 styled Affinities, in which are discussed the relations which the order 

 bears to others, and the most remarkable circumstances connected with 

 its structure in case it exhibits any particular instance of anomalous orga- 

 nization. Geography points out the distribution of the genera and 

 species over the surface of the globe : and the head Properties compre- 

 hends all that is certainly known of the use of the species in medicine, 

 the arts, domestic or rural economy, and so forth. A few genera are 

 finally named as Examples of each order. 



The arrangement of the orders is not precisely that of any previous 

 work, nor indeed do any two Botanists adopt exactly the same plan ; a 

 circumstance which arises out of the very nature of the subject, the im- 

 possibility of expressing affinities by any lineal arrangement (the only one 

 which can be practically employed), and the different value that different 

 observers attach to the same characters. This is, however, of no practical 

 importance, so 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 sub- 

 stitute 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 Exogenoe and Endogenae. It is also certain, that 

 in the actual state of Botany we are more usefully employed in deter- 

 mining the characters of natural groups by exact observation, than in 

 speculating upon points which we have not yet the means of discussing 

 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 organization 

 are explained. This, and the following introductory sketch of the princi- 

 pal modifications of structure, will be found to convey as much information 

 as is absolutely required with reference to the immediate subject of the 

 Work. 



