iv PREFACE 



The planning of a course will be materially assisted by the 

 use of the authors' Laboratory and Field Manual, which is so 

 arranged as to offer a choice between the general requirements 

 of a shorter, elementary course and the details which are only 

 possible when more time can be given to the subject, under 

 excellent conditions of laboratory equipment and with fairly 

 mature students. A glossary of botanical terms employed in 

 this book will be found in the Laboratory Manual. 



Some instructors will prefer to devote most of the year to a 

 study of seed plants ; others will choose to make the story of 

 plant evolution the chief feature and may even prefer to begin 

 with Part II. This portion of the book is the outgrowth of ten 

 years' experience of the junior author in the University of 

 Chicago, where he offered a year's course in general morphology 

 along somewhat similar lines. The treatment given to the 

 thallophytes in Part II will seem to some readers long in pro- 

 portion to that allotted to the other groups of plants. This 

 cannot however be avoided in any account which attempts to 

 present an outline of plant evolution with the important topics 

 of the origin and evolution of sex and of the sporophyte. Fur- 

 thermore, it is very desirable to describe a range of types from 

 which selections may be made according to the material avail- 

 able in different regions of the country. The adaptation of the 

 book to several methods of approach has obviously necessitated 

 slight repetitions of fundamental matter in certain parts. 



Whatever the order of treatment, the authors would urge the 

 importance of sending the student to the plants for as many as 

 may be of his facts and then linking these together by read- 

 ing and class discussion. Undigested laboratory work is little 

 better than none at all, while a reading course without type 

 studies and physiological experiments is a quarter of a century 

 behind the best practice of to-day. No matter where it is to 

 end, the study of botany should begin with a first-hand knowl- 

 edge of plants themselves, best of all, with a knowledge of their 



