PREFACE vii 



Palaeobotany, likewise, has been discussed separately. In comparative 

 courses this would not normally be done, but the type system does not lend 

 itself to expressing the relationships of plants of different groups, and we 

 feel that a survey of fossil plants stratigraphically, as a series of successive 

 floras, has a value of its own, and may also be helpful in comparative studies. 



We were ambitious to make the text sufficiently well illustrated to com- 

 pare favourably in this respect with the German texts which have dominated 

 European science for two generations. They owed their great popularity 

 not least to their wealth of illustrations. The present time is propitious 

 for establishing in other countries the claims of British scientific publications, 

 and we hope that this effort will not be in vain. A very large number of the 

 illustrations are photographs from original material, even in cases where well- 

 known figures were already available. The naturalistic quality of photo- 

 graphs needs no emphasis, and they may afford a pleasing variation from 

 well-known figures which custom has rendered stale. 



The theoretical textbook will appear in four volumes. The arrangement 

 of the chapters follows the evolutionary sequence of treatment, and it is 

 hoped that for this reason students will be able to work with one volume 

 at a time, and therefore save the heavy cost of buying all four volumes 

 simultaneously. 



Messrs Longmans, Green and Co. are about to publish as a companion 

 work to the present book, a " Textbook of Practical Botany," which we 

 have compiled as a laboratory guide for practical studies. The plan of the 

 book follows the same lines as the present theoretical work. The experi- 

 mental sections on Physiology, Ecology, Genetics, etc., are designed to 

 illustrate the theoretical concepts discussed in the later volumes of the present 

 work, while in Morphology the same elementary types which are described 

 here are also treated in the practical book. Only the types intended for 

 more advanced students have been omitted, partly because such practical 

 directions at the advanced level should be largely superfluous, and partly 

 because the material available in the laboratory may change from year to 

 year. 



Students who are commencing a study of Botany, and who are using this 

 theoretical textbook, will find the practical book a great help. It is, moreover, 

 because of the existence of this practical work that experimental details and 

 instructions in laboratory technique generally have been entirely omitted 

 from the present volumes. It is hoped that the " Textbook of Practical 

 Botany " will appear shortly after the publication of Volume I. of the 

 " Textbook of Theoretical Botany." 



We hope that it may be possible for students to use this book from the 

 beginning of their studies onwards, throughout their degree courses. 



