514 THE student's handbook of BRITISH MOSSES. 



This was the Illustrated Guide mentioned above. So viseful and 

 trustworthy was it found to be, and so practical in its working — 

 with its unique feature that it rendered possible the identification 

 of barren mosses — that it was greatly in demand ; and the whole 

 edition was soon exhausted. Once more the scene changes, and 

 we have before us the subject of the present notice. Mr. Jameson's 

 keys and plates no longer stand alone, but, remodelled and redrawn 

 to suit the context, are incorporated in a new handbook written by 

 Mr. Dixon. 



Mr. Dixon's work — it should be said at once — is in no sense a 

 mere compilation, but is a genuine description of the plants from 

 his personal knowledge of them in both the living and the dried 

 state ; and the descriptions are both careful and harmonious. A 

 welcome feature, which is novel to British Moss literature, but has 

 been employed by some foreign writers, is the italicizing of the 

 most distinctive characters of the genera and species — a thoughtful 

 provision which will save us much time in the identification of 

 specimens. To the generic and specific descriptions are appended 

 notes which will prove eminently helpful to the student in the 

 discrimination of plants that are closely allied or deceptively alike. 

 At the same time these notes may, in so far as they are critical, 

 elicit the approval or disapproval of the advanced worker, according 

 to the views he may entertain of the values of species. And this 

 will apply to the subspecies — another innovation which Mr. Dixon 

 has introduced in order the better to express the conclusions at 

 which he has arrived with regard to the claims the plants possess 

 to qualify as species or less than species. He always clearly states 

 his reasons for changing the rank of a plant, and as a genuine 

 worker he has as much right to put forward his own opinion as 

 anyone else has to maintain an opposite opinion. Moreover, the 

 subspecies are as fully described (and figured by Mr. Jameson) as 

 the species, and merely differ in being indicated by an asterisk 

 instead of a number ; hence the introduction of subspecies will in 

 no way diminish the utility of the book to the student for whom it 

 is principally intended, "the primary object of this work being," 

 says Mr. Dixon in his Introduction, "to simplify the determination 

 of our British Mosses for the student, and to make it available, as 

 'far as possible, for a beginner." 



The system of classification is that of the second edition of 

 Schimper's Synopsis (1876), modified, however, in the light of 

 Philibert's researches into the structure and development of the 

 peristome. The Mosses are divided into three subclasses — Sphag- 

 nales, Andreaales, and Bryales, the latter being again divided into 

 two groups — NematodontecB (including three orders — Tetrapliidacece, 

 PolytrichacecB, and BuxhaumiaceoE) and ArthrodontecB. The Artliro- 

 dontecB fall into two subgroups, of which the one — Aplolepidea — 

 contains five orders [Dicranacece, Fissidentacece, Grimmiacea, Tortu- 

 Uicece, Encalyptaceff), and the other — Diplolepidece — is further divided 

 into two sections, the first comprising the rest of the acrocarpous 

 orders, and the second all the pleurocarpous. This arrangement is 

 somewhat novel to British folk ; but, though they will see that the 



