36 The Irish Naturalist, [Feb. 



themselves be a key to the northward or southward range of 

 the plant. Thus, if out of say 40 vice-counties we find the 

 range of a plant is from i to 20, we shall immediately know 

 that it is confined to the southern half of Ireland. It appears 

 to me that the practical advantages of such a plan are much 

 greater than those which arise from a consecutive numbering 

 for the vice-counties of each " province ;" and the scheme which 

 I suggest therefore embodies this principle. A glance at the 

 botanical map in Cybele Hibernica shows that the character- 

 istic plants of Ireland are distributed according to lines which 

 have a general trend north-west and south-east, rather than 

 west and east ; this is also the course followed by the iso- 

 thermal lines of winter and spring ; and I have adopted a 

 system of numbering that follows these natural lines, and 

 proceeds in a regular manner from the extreme south-west of 

 the country to the extreme north-east. Such a plan does not 

 prevent the vice-counties being grouped under the *' provinces " 

 if for any reason this is desired. We should then have the 

 following table ; for the ''provinces" I give the numbering 

 used by Moore and More in Cybele Hibernica : — 

 I. South Atlantic, 



II. Blackwater, . 



III. Barrow, 



IV. Leinster Coast, 

 V. Liffey and Boyne, 



VI. Lower Shannon, 



VII. Upper Shannon, 



