IV PKEFACE. 



sketch of Systematical Botany, treated in the same manner. 

 He undertook the far more difficult task of reducing to their 

 simplest expression the characters that distinguish the various 

 groups in which plants are classified by modern systemati- 

 cal writers ; the object being to diminish, by a very careful 

 and extensive analysis, the difficulties which present them- 

 selves to the student of this branch of the subject. The 

 attempt was made in the form of a series of tables, called 

 the " Alliances of Plants ;" and it has been satisfactory to 

 the Author to find that this too has been advantageous to 

 students, notwithstanding its extreme conciseness. The work 

 thus altered appeared in 1835, under the title of " Key to 

 Structural, Physiological, and Systematical Botany." 



In the edition now offered to students many important 

 improvements have been introduced, without deviating from 

 the original plan of the work. The skill of the wood-engraver 

 has enabled the Author to fill his pages with illustrations, ex- 

 planatory not only of the technical terms employed in Botany, 

 but also of the Natural Orders of plants. An analysis of the 

 latter, upon the plan of Lamarck, an account of De Candolle's 

 celebrated system of arrangement, into which a large number 

 of wood-cuts are introduced, and some new views relating to 

 natural classification, are added to the matter to be found in 

 previous editions : besides which, the whole of the Structural 

 and Physiological part has been corrected with great care, 

 and made to include all the most important views of modern 

 physiologists, so as to present the reader with a view of the 

 state of Botanical knowledge in these departments in the 

 spring of 1841. 



It is hoped that these improvements will render the work 

 what it was originally intended for, a complete Botanical 

 Note-book, wherein all the principal topics which the teachers 

 of Botany introduce into their lectures are arranged methodi- 

 cally. The student will naturally look to his instructor or to 

 more extensive works for explanations of those points which 

 in his Note-book are merely adverted to. 



University College, London, 

 April 1841. 



