XIV PREFACE 



follows: Prof. W. L. Bray and the New York State College 

 of Forestry (Syracuse University), Fig. 266; Dr. N. 

 L. Britton and Charles Scribner's Sons, Figs. 341 and 

 379; Prof. D. H. Campbell and The Macmillan Co., Figs. 

 275, 283, 140, 141, and 146; Prof. F. E. Clements and 

 Henry Holt and Co., Fig. 27; Mr. Frederick V. Coville 

 and the U. S. Department of Agriculture, Division of 

 Publications, Fig. 336; Prof. H. H. Dixon and The 

 Macmillan Co., Fig. 35; Doubleday Page & Co., Fig. 225; 

 Prof. H. Garman and the Kentucky Agric. Exp. Station, 

 Fig. 228; Prof. William F. Ganong and Henry Holt and 

 Co., Fig. 69; Prof. Patrick Geddes and John Murray, 

 Fig. 240; Geological Survey of Ohio, Fig. 581; Prof. W. 

 D. Hoyt and the Bureau of Fisheries, Washington, D. C., 

 Fig. 177; the Ohio Geological Survey, Fig. 412; Prof. 

 A. C. Seward and The "Cambridge University Press (Lon- 

 don), Figs. 413 and 414; Prof. D. H. Scott and A. & C. 

 Black, Figs. 415 and 418; Dr. Albert Schneider and 

 Willard N. Clute & Co., Fig. 238; Prof. Hugo de Vries 

 and The Open Court Publishing Co., Figs. 401 and 402; 

 Prof. G. R. Wieland and the Carnegie Institution of 

 Washington, Figs, 421-427; Prof. S. W. Williston, Fig. 432. 



The conception of diagramning life-cycles, as in Figs. 

 321, 329, and others, appears to have originated with 

 Prof. John H. Schaffner, of Ohio State University. These 

 diagrams possess admirable teaching value. 



It is a pleasure for the author to acknowledge a large 

 indebtedness to his colleagues on the staff of the Brooklyn 

 Botanic Garden, and especially to Dr. E. W. Olive, whose 

 careful and critical reading of the entire manuscript and 

 proof has robbed the reviewer of much that would have 

 been rightfully his, and has added much of fundamental 



