46 



SYNOPSIS OF ORDERS AND GENERA. 



It should be observed, that the characters of the Orders and 

 Genera, in the following synopsis, are drawn up with a view to 

 the Mosses of the British Isles alone, and not to Mosses in general, 

 the object being to facilitate the reference of British species to 

 their proper genera. In the enumeration of species, on the con- 

 trary, exotic genera and species have been constantly kept jn. 

 view in the definitions. In scarcely any tribe of plants, however, 

 is it so difficult to draw up precise characters, as the evident 

 affinities of particular species militate more than usually against 

 definite circumscriptions. Generic characters were originally con- 

 fined to the parts of fructification ; but if natural groups are 

 desired, it is absolutely necessary to comprehend also in our 

 characteristic phrases particulars about the mode of branching, 

 and the nature of the leaf-cells, where these admit of definition. 

 In a very few cases I have been compelled to propose genera, where 

 anomalous species did not admit readily of association with 

 others, though I have done so with reluctance. 



Section I.— PLEUROCARPI. 

 Fruit lateral, or at the tips of very short branches. 



Oedeb I. FONTINALEI. 



Sporangia sessile or subsessile; peristome double; inner 

 peristome conical, cancellate. 



Genus 1. Fontinalis. — Sporangium sessile; veil mitriform. 



