4 INTRODUCTION. 



their morphology is more special and difficult. Wherefore it is 

 better to treat them separately and subsequently. This will be 

 done in a third part, by an associate devoted to Cryptogamic 

 Botany. 



9. Thus the field is here left clear for the Structural Botany 

 of Phaenogamous or Flowering Plants, with which the study of 

 the science should naturally begin. In theory it may seem 

 proper to commence with the simplest plants and the most ele- 

 mentary structures ; but that is to put the difficult and recondite 

 before the plain and obvious. The type or plan of the vegetable 

 kingdom, upon which morphological botany is grounded, is fully 

 exemplified only in the higher grade of plants, is manifest to 

 simple observation, and should be clearly apprehended at the 

 outset. 



