xii Preface 



composition of associations are as follows : d = dominant, 

 Id — locally dominant, Isd = locally subdominant, a - abun- 

 dant, Za = locally abundant, /= frequent, o = occasional, 

 r = rare, vr = very rare. It is to be understood of course 

 that these symbols refer to frequency within each associa- 

 tion as a whole, and have no reference to frequency in the 

 country at large. 



A. G-. T. 



Grantchbster, Cambridsb, 

 July, 1911. 



