PREFACE. 



THE great want of a guide to our recently much-extended Moss- 

 Flora, and the solicitation of numerous friends, have induced the Author 

 to commence a work which he trusts will meet the requirements of all 

 who study these interesting plants. 



The cell structure of the leaves, so important in the distinction of 

 genera and species, will receive due attention both in the figures and 

 descriptions, and the bibliography, while not attempting to be exhaustive, 

 will be ampler than has hitherto appeared in any British work ; the 

 records of localities for all but common species will also be numerous, 

 the mark ! after any of these indicates that the specimen has been 

 examined, and ! ! that it is also in the Author's herbarium. 



In the nomenclature, the oldest published name has been adopted 

 when there were no sound reasons to the contrary, and it is greatly to 

 be deplored that so little attention has been paid to the laws drawn up 

 for our guidance, for an author is not at liberty to change a specific name 

 on transferring it to a new genus, nor to supersede by a new name, one 

 previously published, even by himself. 



The term peristome is restricted to the outer or parietal series of 

 appendages, when this organ is double, the inner, proceeding from the 

 spore-sac, being distinguished as the endostome, and the adjective termination 

 to specific names in honour of individuals is also altered to the genitive 

 of the noun, as Brownii for Brownianum (see Lindley's Introduction to 

 Botany, 2 ed. p. 458). 



The arrangement of the families and genera is principally in accord- 

 ance with Professor Lindberg's admirable program, " Utkast till en natiirlig 

 gruppering af Europas lladmossor med toppsittande frukt " (1878), the most 

 natural which has yet appeared ; in this the cleistocarpous mosses as 

 in Mr. Mitten's system are regarded as imperfectly developed forms of 

 various stegocarpous families, with which they agree in everything but 

 a separable operculum, and the genera are framed on a broader and more 

 rational basis, just as our best botanists now deal with phaenogamous 

 plants. 



