16 



Proceedings of the Royal Irish Academy. 



The maximum in any Irish county-division is 24 (or 72 per cent. 

 of the Irish Hst) in South Kerry, West Cork, and "Waterford, the 

 minimum 2 (or 6 per cent.) in Kildare. Our map works out veiy 

 prettily : — 



Fig. 8. — Distribution of " Atlantic " plants. 



The group is seen to be essentially coastal — partly on account of 

 the plentiful sprinkling of maritime species, partly because the 

 remainder are largely plants of the rough country which often 

 accompanies the older rocks ; such countiy as is found in the home of 

 the gi'oup in Devon, Cornwall, and Wales, and in Ireland round a 

 great portion of the seaboard. The group also shows an increase south- 

 ward, and attains its full luxuriance round the shores of the southern 

 half of Ireland. 



Before proceeding to briefly sum up the features brought out by 

 the foregoing series of maps, it will be well to consider one important 

 factor in plant-distribution. Apart from climate, the most potent 

 influence affecting the flora is undoubtedly soil, and it is the 

 presence or absence of lime in soils that most affects the vegetation 

 which they support. Ireland consists, roughly speaking, of a great 

 plain of Carboniferous limestone occupying the centre, with more 



