vi Preface 



to which they have been accustomed in the British 

 Floras that have hitherto appeared, and to serve as an 

 introduction to the use of the Syllabus, the Natiirliche 

 Pflanzenfa}nilie7i and the Pflanzenreich. 



The major divisions of the vascular plants with 

 their diagnoses are taken, to a large extent, verbatim 

 from the Syllabus der Pflanzenfamilien (7th Edition 

 1912). 



Professor Engler and his publishers have most 

 kindly and readily accorded their assent to this very 

 free use of their publication. 



In a few cases Engler's arrangement has been de- 

 parted from. 



Thus the nomenclature of the larger divisions of 

 Pteridophyta has been somewhat modified in order to 

 secure uniformity in the terminations of the names of 

 Orders (Reihen). Prof Bower's arrangement of the 

 Leptosporangiate Ferns into Simplices Mixtae and 

 Gradatae has been adopted as representing the most 

 rational grouping, though the distinct suborder of 

 Filicales, Hydropteridineae, has been retained owing 

 to the difficulty of assigning with certainty the Marsi- 

 liaceae and Salviniaceae to their proper places in the 

 Eufilianean series. 



The Family Polypodiaceae, practically equivalent to 

 the Mixtae of Bower, has been retained and divided 

 into tribes according to the arrangement of the Syllabus, 

 since our knowledge of the Systematics of this intricate 



