PREFACE vii 



the sequence used by the teacher. For example, work on 

 leaves, stems, roots, and seeds may come in any order, and 

 may well differ according to the availability of material or the 

 conviction of the teacher. It so happens that the book begins 

 with leaves, but those teachers who prefer to begin with seeds 

 should do so. 



In the matter of illustrations, there have been many im- 

 provements, eliminations, and additions. All of this work 

 has been done or directed by my assistant, Dr. W. J. G. Land, 

 whose skill in photography has been made use of freely and 

 whose cooperation has added much to the value of the book. 

 Unless otherwise credited, all illustrations have been prepared 

 for this volume or those previously mentioned. 



JOHN M. COULTER. 



THE UNIVERSITY OP CHICAGO, 

 September, 1905. 



