4 P EFFACE 



The descriptive text follows in the main the sequence of topics of 

 Gray's " Lessons in Botany," and certain parts of that book have been 

 retained, as occasional paragraphs will show. In view of the relation 

 of the present book to tlie " Lessons " as indicated on the title-page, 

 the writer has felt free to adopt the phraseology of Dr. Gray wherever 

 desired, without quotation marks. A considerable number of descrip- 

 tive terms and definitions applied to the leaf and the flower have 

 been taken from the " Lessons," being now placed apart, for the use 

 of the classes making a somewhat detailed study of phanerogams in 

 a systematic way. But the greater part of the descriptive text 

 throughout is new, the chapters on cryptogams and on physiology 

 being entirely so. 



In an endeavor to combine the best features of newer methods 

 with the lucidity and definiteness which have given Dr. Gray's text- 

 books their extraordinary merit, the present book departs from its 

 predecessor in paying more attention to the life of plants, as con- 

 trasted with mere form. The writer has aimed to give due promi- 

 nence to function which underlies form, that is to physiology and the 

 relations of plants to their surroundings. Yet while seeking properly 

 to emphasize the ecological aspects of plant life, he believes that ecol- 

 ogy should not be made the basis of elementary botany. It seems to 

 him that a course should be built primarily upon a careful study of 

 form, leading to some power of intelligent discrimination in morphol- 

 ogy and of accurate description in the technical language of the 

 science. Equally essential are certain perfectly definite principles of 

 vegetable physiology. The core of any rational elementar}^ course 

 is thus believed to be concrete, embodied in precise and more or less 

 technical language, and measurably endowed with a quality which 

 some would with disfavor characterize as formalism. The writer be- 

 lieves that the body of concrete instruction is not likely soon to be 

 displaced by the less definite and as yet more tentative generalizations 

 of the latest Ecology. 



The Appendix is an essential part of the book, but is primarily 

 addressed to the teacher. It contains suggestions in regard to equip- 

 ment, books, materials, experiments, and additional exercises, as well 

 as pedagogical methods. 



The writer appreciates, and here takes occasion to acknowledge, 

 the care with which Mr. C. E. Faxon and Mr. F. Schuyler Mathews 

 have made many new drawings for this book. Thanks are due to the 

 staff of the Gray Herbarium for aid in proof reading, especially to 

 Miss M. A. Day, Librarian. The writer is deeply indebted for advice 

 and criticism to Mr. William Orr, Principal of the High School, 

 Springfield, Massachusetts. Above all, the writer would acknowledge 

 his great obligation to Dr. B. L. Robinson, Asa Gray Professor of 

 Systematic Botany in Harvard University. 



R. G. LEAVITT. 



