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 
