20 ADVERTISEMENT TO THE FOURTH EDITION. 



size and cost of the book, thereby rendering it less 

 useful than it otherwise would have been. In the 

 present edition, these expensive illustrations will be 

 reduced in number, though not in utility ; as every 

 necessary illustration will be retained of all the best 

 grasses, together with their dissections on the same 

 plate, to which all requisite references will be ap- 

 pended. 



