PREFACE 



This book has been prepared in response to many requests that I 

 have received from colleagues. Although the present volume fol- 

 lows the general lay-out of my first book An Introduction to the 

 Study of Algae ^ there has been so much rearrangement, the com- 

 plete rewriting of many chapters and the addition of new ones, 

 that it cannot be considered a second edition of the first book. I am 

 particularly grateful to the Syndics of the Cambridge University 

 Press for releasing the original copyright so that it has been possible 

 to use some portions of the first book. In recent years considerable 

 advances have been made in the study of the algae and this has 

 affected, not only our knowledge of their life histories, but also our 

 views on phylogeny. These new results have necessitated much 

 rearrangement of material. There has also been extensive new 

 work on the ecology of the algae, so that the chapters on marine 

 algal ecology and ecological factors are more or less completely 

 new. The same is true also of algal physiology. In order that the 

 survey should be more complete there is a chapter briefly describ- 

 ing the historical aspect of the subject, and also a chapter on the 

 economic uses of algae. 



The purpose of the book remains the same as my first volume, 

 namely to provide a general survey of all aspects of the algae such 

 as may be required by a University undergraduate, with selected 

 portions (marked by an asterisk) that can be used by first year 

 students or which are suitable for use in schools at the sixth form 

 level. The type method of instruction has again been employed 

 because continued experience has not changed my belief in it. I 

 still feel, however, that no study of the algae is complete without 

 reference to the other aspects which have been included. I am 

 aware that not everyone will agree with what has been included and 

 material that has been excluded, nor with all the views expressed, 

 but where there are divergencies of opinion, I have tried to see that 

 the other view is also presented or made known. This is perhaps 

 particularly true in the chapter on Evolution. 



There are a number of excellent works available to advanced 

 students and research workers, and the present volume is not 

 intended to compete with them in any way. Apart from those 



