PREFACE. 



This work is the outcome of four years' study on the Harrison 

 Foundation in the University of Pennsylvania. It would have been 

 difficult or impossible without the generous support given by the Provost 

 and the Board of Trustees. In the University Botanic Garden over 

 thirty species and varieties of waterlily were cultivated, and several 

 hybrids originated. These and other collections of living plants furnished 

 excellent material for the present review of the group. 



Nothing like a complete synopsis of the Waterlilies has hitherto 

 been put before the English-speaking world. DeCandolle made a special 

 study of the genus Nymphaea for his Prodromus, and both Lehmann 

 and Planchon gave much attention to the genus from 1850 to 1853. 

 Beginning in 1855 and continuing until 1888, a number of exhaustive 

 treatises by Robert Caspary went far toward perfecting our knowledge 

 of these plants. Indeed, had the learned doctor of Konigsberg 

 assembled his vast knowledge into one connected whole, the present 

 work would be needed chiefly as a translation. Since his day, however, 

 great strides have been made in the culture and hybridization of water- 

 lilies, with the result that they now appear in almost every collection 

 of plants. Already by crossing and recrossing and the use of horti- 

 cultural names, serious confusion exists concerning the identities of the 

 parent species. It has therefore seemed important to bring together 

 the knowledge of the genus in all of its botanical relations and in its 

 bearings on human life and history. In the present attempt there may 

 be many omissions, in spite of the utmost efforts in collating the material, 

 but the paper may serve to show how incomplete is our knowledge of 

 any one group of plants, and it is hoped that it may make the way of 

 the future investigator easier. 



In the adoption of the generic name Nymphaea, the writer regrets 

 that he is at variance with a number of American botanists for whom 

 he has the utmost respect ; but a glance at the synonymy of Nymphaea, 



