and I have felt obliged to treat the varietal forms, especially of 

 some of our more polymorphous species, in what may perhaps be 

 deemed an eclectic rather than an exhaustive fashion. I have also 

 endeavoured to describe the species in language as free from 

 technicalities as possible, knowing that one great deterrent from 

 a more general study of plants, especially of cryptogams, is the 

 difficulty presented by the nomenclature and the descriptive 

 terms. It is impossible, on the grounds of both brevity and 

 accuracy, to avoid the use of technical terms, but I have 

 endeavoured to use only such as seemed really necessary, and I 

 believe that, with the aid of the Glossary, there is nothing in the 

 work which will be found unintelligible by the ordinary student. 



The Plates have been drawn by the Rev. H. G. Jameson, to 

 whom also I am indebted for the Keys to the Genera and Species, 

 and for advice and suggestion throughout the work, the MS. of 

 which has all passed through his hands. The responsibility, 

 however, for the contents of the book must rest upon my shoulders, 

 and any names or combination of names published here for the 

 first time must be cited with my name alone. 



Of the short-comings of the book no one can be more 

 conscious than its authors. It would be inevitable, in dealing 

 with a subject of this kind, even with the greatest facilities for 

 attaining accuracy, that errors should creep in, and facts be 

 overlooked ; and when the whole of the work has to be done in 

 the scanty leisure snatched from exacting professional duties, the 

 obstacles in the way of accuracy are greatly increased. I can 

 only ask the student to bear this in mind in passing his judgment 

 on the present work, and to be assured that any suggestions, 

 corrections or additions will be exceedingly welcome. 



H. N. DIXON. 

 East Park Parade, 



Northampton, 



May, i8g6. 



