PREFACE. 



THIS compendious treatise is designed to furnish classes 

 in our schools and colleges with a suitable text-book of 

 Structural and Physiological Botany, as well as private 

 students with a convenient introductory manual, adapted 

 to the present condition of the science. The favor with 

 which the former editions have been received, while it has 

 satisfied the author that the plan of the work is well 

 adapted to the end in view, has made him the more desir- 

 ous to improve its execution, and to render it a better ex- 

 ponent of the present state of Physiological Botany. To 

 this end the structural and physiological part of the work 

 has been again almost entirely rewritten for this third edi- 

 tion, and much enlarged. The chapter on the elementary 

 structure of plants, or vegetable anatomy, the sections on 

 the internal structure of the stem, on phyllotaxis and its 

 relations to floral structure, and on the symmetry and 

 morphology of the flower, may be particularly adverted to, 

 as having been altogether recast and greatly extended. 

 The want of space and time has prevented a similar exten- 

 sion of the systematic part of the work, especially of the 

 Illustrations of the Natural Orders. This portion, however 

 amplified, could never take the place of a Flora, or System 

 1* 



