QK 



101 



PEEFACE 



IN the preface to Dr. Marcel Hardy's Introduction to 

 Plant Geography, Professor Herbertson wrote, ' it will 

 be followed by a more advanced book '. This ' more 

 advanced book ' is the volume now published. 



Many causes have contributed to delay its appearance : 

 the death of Professor Herbertson ; the departure of the 

 author to South America ; the War and its aftermath, 

 which have rendered so extremely difficult everything 

 connected with the publication of books : but the proofs 

 have been fully revised, and many new photographs 

 have been inserted. 



It may be taken as in some sort an expansion of 

 Part III of the earlier work, since the slight ' survey of 

 the continents ' given there has served as the plan for 

 the new book, and has been expanded into a full dis- 

 cussion of the conditions in which plants nourish, and 

 their distribution in the great geographical divisions 

 of the earth. An index of the plants mentioned is 

 appended, with the scientific or popular name, as the 

 case may be : where the author has used a precise name ; 

 the exact equivalent is given ; where a genus only is 

 indicated, the corresponding generic term is set down, 

 unless some particular species is peculiarly characteristic 



