VI PREFACE. 



of service to field botanists, and may perhaps encourage 

 others to interest themselves in these somewhat neglected 

 plants, by removing some of the difficulties encountered 

 in dealing with them. 



A bibliography has been compiled to assist those 

 wishing to pursue the study of the group. We have 

 tried to make this as complete as possible, but cannot 

 hope to have included all the many and various detached 

 papers bearing on the subject which have appeared in 

 serial publications and in the journals of societies and 

 academies, some of them not readily accessible. 



In addition to the many friends and correspondents 

 mentioned in the first volume as having rendered us 

 assistance in the preparation of the work, we have to 

 acknowledge with grateful thanks the kind help afforded 

 us by Mr. Anthony Gepp, of the Department of Botany 

 of the British Museum, in connexion with the list of 

 exsiccata, and to the geologists whose names we mention 

 in the geological sketch. 



JAMES GROVES. 



G. R. BULLOCK-WEBSTER. 



July, 1924 



