10 Proceedings of the Royal Irish Academy. 



All of tliese are classed by Watson as of purely Highland type except 

 SuluJaria and Vaccinium ViUs-Idcea, which he ranks as Highland- 

 Scottish, and Sesleria, which goes as Highland-Intermediate. Plants 

 of. this group are thinly spread in Ireland, as is to be expected from 

 the conformation of the country ; but taking into account the charac- 

 ter and altitude of the mountain-groups, the total does not fall much 

 below what might be expected. With the vertical distribution of the 

 species, the present paper is not concerned; but some interesting 

 points become apparent from the mapping of their horizontal range. 

 Here the maximum is 29 (or 69 per cent.) in West Donegal, the 

 minimum in Mid and East Cork. (Fig. 3.) 



Being essentially a mountain group, it is desirable to contrast their 

 distribution with that of high land in Ireland — say of over 1000 feet 

 elevation. The actual distribution of land of over 1000 feet ia 

 Ireland is shown in fig. 4. 



But for purposes of comparison, it may be well to construct a 

 graduated map on the same principle as the floral maps (fig. 5). A 

 dijfl&culty is encountered here, for the amount of high land in two of 

 the divisions — Wicklow and South Kerry — so far sui'passes that which 

 is foxind elsewhere, that were an evenly graduated scale employed, the 

 varying elevation of the rest of the country would not be brought out. 

 We therefore employ the following scale : — 



0—25 square miles over 1000 feet elevation, -vrMte 

 26- 50 ,, ,, „ = 



51 - 75 ,, „ ,, =1=1- 



76-100 „ „ „ i|i|i 



200-225 ,, ,, ,, black 



For comparison, I add the distribution of ground over 2000 feet 

 elevation (fig. 6), according to the scale — 



square mile over 2000 feet, wUte 

 up to 1 ,, ,, ^= 



1 to 3 „ „ =1=1= 



3 to 8 ,, „ i|i!i 



20 to 25 ,, ,, black 



If we contrast these two maps with map 3, we have|[the materials 

 for comparing the distribution of " Highland " plants in Ireland with 

 that of high ground. In area of high ground, whether the 1000 foot 



