PREFACE. 



IX 



science of natural history is far greater than can be esti- 

 mated by the number or size of the volumes which he wrote, 

 and is to be traced to his habit of acute observation of facts 

 and the logical accuracy with which he arranged them. 

 He made his knowledge of the structure and physiology 



of plants subservient to a great plan for their arrange- 

 ment, and this plan, when carefully examined, will be found 



to contain the fundamental principles of all the more 

 recent scientific systems in natural history, and to have 

 laid the foundation of the views of a natural classifica- 

 tion of the vegetable kingdom put forward in later times. 



E. L. 



22, Old Burlington Street; 

 'February 1846. 



