IV. 



It is too mucli to expect that a work of this kind will be 

 free from mistakes, and I hope that readers will help me by 

 pointing out any corrections that should be made, or by offer- 

 ing suggestions for the improvement of the key. 



Since, in the key to the species, and in the section of 

 ecological notes the genera are arranged alphabetically, and 

 a full table of contents is given for the sections dealing with 

 the plant succession and economic applications, it has not been 

 thought necessary to add an index. 



J. W. BEWS. 



]S"atal University College, July, 1918. 



