iv Preface. 



page 125, shows the leading facts. It seemed patent to the writer that 

 all of the general, and several special, arguments against a change of 

 name are particularly cogent in the present example. The new code, 

 however, proposed by a committee of the Botanical Club of the American 

 Association for the Advancement of Science, seems to sanction the nomen- 

 clature here chosen. 1 In the use of specific names, authorities have been 

 omitted wherever possible, since the names adopted in Chapter V are 

 followed. Citations of literature are based on the bibliography on pages 

 243 to 263. 



Throughout the time occupied by the preparation of this work, I have 

 been deeply indebted to Professor John M. Macfarlane, to whom I desire 

 to express my gratitude. 



To Mr. William Tricker, formerly of Riverton, N. J., and through him 

 to the Henry A. Dreer Co., of Philadelphia, I am under obligation 

 for the privilege of studying their magnificent collection of waterlilies. 

 Acknowledgment is also due to Dr. J. W. Harshberger, of the Uni- 

 versity of Pennsylvania, and Dr. J. N. Rose, of the National Herbarium, 

 for suggestions and herbarium material ; to Mr. A. J. Mela, of Helsingfors, 

 Finland ; J. J. Soar, of Little River, Fla.; Wm. Gollan, Saharanpur, India ; 

 Wm. Fawcett, of Kingston, Jamaica ; R. M. Gray, gardener to O. Ames, 

 North Easton, Mass. ; Gopal Chandradatta, Calcutta, India ; Sr. Alberto 

 Lofgren, director of the Botanical Garden of Sao Paulo, Brazil ; the director 

 of the Royal Botanic Garden of Tokyo, Japan ; to the Gray Herbarium, 

 Boston Natural History Society, Massachusetts Horticultural Society, 

 Columbia University ; to the Academy of Natural Sciences of Philadelphia 

 for library facilities; and to John B. Lieberg, Joseph H. Painter, Chas. C. 

 Abbott, Prof. Conway MacMillan, Albert J. Edmunds, E. D. Sturtevant, 

 and C. G. Pringle for various courtesies. Mr. Frederick V. Coville and 

 Mr. J. C. Bay, of Washington, D. C, have also given helpful aid and 

 criticism while the matter was going through the press. 



In order to give the greatest possible accuracy to the taxonomic 

 portion of the monograph, I was enabled by the trustees of the Carnegie 

 Institution of Washington to examine important type material in several 

 European herbaria, viz, in Kew, British Museum, Linnaean Society, 

 Museum d' Histoire Naturelle, the herbaria of De Candolle, Delessert, and 

 Barbey-Boissier, and the herbaria of Munich, Berlin, and Copenhagen. The 

 results of this trip were very valuable, thanks to the courteous assistance 



'Bulletin Torr. Bot. Club, 31: 249-290. May, 1904. 



