PREFACE V 



from "Plants" and "Elementary Studies in Botany"; to C. C. 

 Curtis and Henry Holt & Company for permission to use figures 

 174, 178, 270, 276 from "Nature and Development of Plants"; to 

 Henry Holt & Company for permission to use figures 143, 153, 285, 

 and 290 from Kerner and Oliver; to W. C. Stevens and D. C. 

 Heath & Company for permission to use figures 142, 166, 225 

 from "Introduction to Botany" ; to J. Y. Bergen and Ginn & Com- 

 pany for permission to use figures 86 and 186 from "Foundations 

 of Botany" ; to J. Y. Bergen, 0. W. Caldwell and Ginn & Company 

 for most of figure 433 from "Practical Botany"; to the Ferguson 

 Publishing Company for permission to use figures 97, 104 and 312 

 from "Elementary Principles of Agriculture" ; to B. M. Duggar and 

 Ginn & Company for permission to use figure 319 from "Fungous 

 Diseases of Plants"; to Hugo DeVries and the Open Court Pub- 

 lishing Company for permission to use figures 472 and 473; to 

 N. L. Britton and Charles Scribner's Sons for figure 392; to 

 D. H. Campbell and MacMillan Company for figure 391 taken 

 by permission from "University Text-Book of Botany" ; to Hugo 

 DeVries for permission to use his photo; and to E. P. Dutton & 

 Company for photos of Charles Darwin, Hugo DeVries and 

 Gregor Mendel, taken by permission from "Recent Progress in 

 the Study of Variation, Heredity and Evolution" by Robert H. 

 Lock, pubhshed by E. P. Dutton & Company, New York; to 

 F. L. Sargent and Henry Holt & Company for permission to use 

 figure 163 from "Plants and their Uses"; to the authors of publi- 

 cations in journals and bulletins from which figures have been 

 used, as figure 318 from one of Harper's papers on the reproduc- 

 tion of Fungi, the figures from bulletins on genetics by Emerson, 

 East, and Hayes, the figures of the floral structures of trees by 

 Burns and Otis, and a number of other figures from various 



authors. 



J. N. MARTIN. 



Ames, Iowa. 

 May 5, 1920. 



