PREFACE 



I wiSH to thank Professor A. C. Andrews of the 

 University of Miami for the great help he has been 

 in the preparation of this volume. I sometimes refer 

 to him as A.C.A. Expert botanical knowledge is 

 essential for the sokition of many problems that have 

 arisen, esj^ecially in the compilation of the Index of 

 Plants. My rough draft of this he revised, making 

 many additions : these amount to several pages. 

 For the errors that inevitably remain in my work I 

 alone am responsible. 



My thanks are also due to the stafF of the Cam- 

 bridge School of Botany and to Professor C. O. Brink 

 of the same University. 



