.Tin ATJTHOKS PBEFACBi 



State Collections at my disposal. In America, Drs. Knowlton, 

 Holliek, and Berry, and Mr. White were most kind and helpful ; 

 as were Dr. Britton of New York, whose great Institute gave 

 me hospitality and the use of the plant collections for some 

 time, and Prof. Jeffrey of Cambridge, who showed me several 

 of his valuable specimens. In Canada, the Director of the 

 Geological Survey was most kind in Ottawa, and also loaned 

 some specimens for further examination in London. In Europe 

 the following must be specially mentioned: — Prof. Eothpletzi 

 Dr. Gothan, Dr. Halle, Dr. Eavn, Prof. Seward, Prof. Oliver, 

 and Dr. Arber, for all have from time to time exerted them- 

 selves on my behalf, loaned specimens, or given me help. 

 In the British Museum I also have to thank Dr. Smith 

 "Woodward, Dr. Eendle, and Dr. Bather, besides Mr. Gepp 

 and Mr. Newton : while Mr. Sherborn's unique knowledge of 

 old and troublesome books and incomplete bibliographical 

 references has several times proved invaluable. 



MAKIE C. STOPES. 

 August, 1913. 



