Treface 



that fuller treatment than that originally accorded 

 seemed desirable. 



The plan of the book is as follows : First, the 

 history of the discovery of the method of flower 

 fertilization is carefully traced, then the method is 

 worked out and explained in the case of an abstract 

 flower, and the modifications of the various flower 

 organs, due to their adaptation to their insect visit- 

 ors, by means of natural selection, pointed out. 

 The remainder of the book consists of twenty-five 

 concrete examples of different methods of cross- 

 fertilization. These examples stand as types of the 

 ordinary processes adopted by nature. 



It is thought that no method of preventing self= 

 fertilization and insuring the opposite result exists 

 among our wild flora that has not its prototype in 

 these pages. As Gibson himself savs of the orchids : 

 " Each new species affords its new surprise in its 

 special modification in adaptation to its insect spon- 

 sors ; " but the general method is based on one of the 

 plans illustrated. 



In addition to furnishing a complete exposition 

 of the processes involved, the book will be found a 

 guide to the habits and characteristics of many 

 individual species, tables being appended giving 

 all the data at present available for about two 



ix 



