iv PREFACE 



In deference to tlie wislies of many teachers, chapters on 

 Plant Breeding, on Useful Plants, and on Timber and Forestry- 

 have been added. This matter may be used as a basis on which 

 to build further reading for brief essays. Or it may suggest 

 elementary inTCStigations into the horticulture, the agricul- 

 ture, or the forest conditions of the student's own neighbor- 

 hood. The study of useful plants and their products may be 

 taken up from Chapter xxx as the topics suggest themselves 

 in earlier portions of the text, i.e., seeds as food and medicine 

 in connection with Chapter ii, and so on. 



The author wishes to thank Dr. A. A. Lawson, now of the 

 University of Glasgow, Scotland, who read the manuscript of 

 Chapters xxii-xxvii, for many valuable suggestions. Thanks 

 are also due to Professor D. P. Penhallow of McGill Uni- 

 versity, Montreal, for suggestions on Chapter xxviii, and to 

 Dr. H. von Schrenk of St. Louis for aid on the chapter on 

 Forestry. 



Grateful acknowledgments are due for the use of illustra- 

 tions copied for various figures as follows : D. H. Campbell, 

 208, 216 ; H. W. Conn, 170, 171, 175; W. G. Parlow, 160 ; 

 A. E. Frye, 232, 234 ; C. P. Hodge, 225 ; A. D. Hopkins, 237; 

 D. S. Jordan, 223; F. Both, 236; J. H. Schaffner, 208; H. J. 

 Webber, 224. Special mention should be made of the unpub- 

 lished yucca drawing by Mrs. Grace Johnson Vieh, loaned by 

 Professor William Trelease and used for Fig. 132. Some of the 

 outs above mentioned have been re-drawn, others are printed 

 from the original wood engravings or zinc etchings. 



A large proportion of the illustrations in Chapters xxiV- 

 XXX have been re-drawn for the present book from the most 

 authoritative sources by E. E". Fischer, F. S. Mathews, and 

 C. H. L. Gebfert. 



J. Y. B. 



Cambkidge, Massachusetts 



