Viii INTEODUCTION. 



Grateful acknowledgment for assistance in the preparation of 

 this volume is tendered to Dr. John K. Small, for critical compara- 

 tive work as regards plants of Florida and for proof-reading; to 

 Mr. Percy Wilson for bibliographical work, proof-reading and in- 

 dexing ; to Mr. W. R. Maxon for information relative to the Ferns ; 

 to Mrs. N. L. Britton for her contribution of the treatment of the 

 Musci; to Professor Alexander W. Evans for his contribution of 

 the Hepaticae ; to Professor Lincoln W. Riddle for the chapter on 

 Lichens; to Dr. Marshall A. Howe and Mr. Frank S. Collins for 

 the chapters on Algae; to Mr. Charles S. Boyer for the list of 

 Diatoms; to Dr. Fred J. Seaver and Dr. William A. Murrill for 

 their work on the Fungi ; and to Mr. L. J. K. Brace for many notes 

 and for lists of common names of plants. Much information regard- 

 ing species was also obtained from the Royal Gardens, Kew, Eng- 

 land, and from the British Museum of Natural History, and is 

 highly appreciated. 



