Preface xi 



as yet, sufficiently extensive to be of use. It is believed, 

 nevertheless, tbat the statements made about the relation 

 of soils to the different types of vegetation, which are 

 partly based on analysis and partly inferred, are essentially 

 accurate, and afford a sound basis of classification. It is 

 beKeved, in fact, that the classification of vegetation and 

 the treatment of the genetic relations of plant-communities 

 are in advance of anything hitherto attempted, though 

 modifications are of course to be expected as knowledge 

 advances. 



The field of analytical and experimental ecology lies 

 widely open to workers able and willing to devote 

 themselves to the laborious tasks involved in the attack 

 on the various problems underlying the phenomena of 

 vegetation. 



The chief obstacle to the rapid development of ecology 

 on fundamental lines is the laborious and time-consuming 

 nature of the work and the chemical and physical training 

 required for its prosecution. It is hoped that this book 

 will serve to call attention to many of the more immediate 

 problems. 



Nomenclature of specific immes. The nomenclature of 

 species and the order in which they are placed in the 

 general Lists for the most part follow the 10th edition 

 of the London Catalogue (1908). To continental readers 

 the adherence to the system of Bentham and Hooker 

 wiQ seem an anachronism, but the convenience of 

 following a recognised standard list of British plants 

 dictated this course. 



Symbols denoting frequency. The symbols denoting 

 the frequency of species in the general lists of the 



