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Proceedings of the Royal Iriah Academij, 



lanuginosum are present, and, further, the surface of the ground is, as 

 a rule, much broken up, so that pools often of considerable size are 

 also present. The association in this case, then, has not been named so 

 much from its dominant plant — which, as will be seen presently, is 

 usually Calluna — as from its most conspicuous one. 



The Racomitrium association hence in some areas, as notably, for 

 instance, on the flat land immediately south of Moutpelier dry gap, 

 is apparently a specially wet form of the Calluna heath, and Erica 

 Tetralix figures considerably in its composition. The bosses of Racomi- 

 trium liere are not, as a rule, very large, but pools of water are 

 plentiful. Scirpus, Eriophorum, and Empetrum are fairly abundant, as 

 well as Brosera and Pinguicula. In other areas, as, for example, 

 south-east of the summit of Killakee, and along a strip running north 

 from Lower Lough Bray, the association more nearly approaches a 

 Scirpus bog in which innumerable and fairly large bosses of Racomi- 

 trium occur. On still higher ground the association sometimes con- 

 tains a fairly conspicuous amount of cotton-grass. Finally we have 

 mapped two not very large areas under this heading which differ very 

 considerably from the above three types. They are a small area on 

 the summit of Prince AVilliam's Seat (1822 feet), and a larger one on 

 the summit of Killakee Mountain (1761 feet). Characteristic of these 

 two spots is the fact that the peat doubtless formerly present has now 

 been almost entirely denuded away, exposing the gravelly barren soil 

 derived from the granite. On these dry areas the Racomitrium spreads 

 horizontally, rather than into high bosses, and the whole aspect is 

 that rather of a moss-tundra. Along with the Racomitrium we find 

 plentifully interspersed Empetrum and dwarf Calluna^ while much 

 less abundant are the following species : — 



Vaccinium Myrtillus. Festuca ovina. 



Erica cinerea. Juncus squarrosus. 



TJlex Gallii. Luzula multiflora. 



Deschampsia flexuosa. Cladonia rangiferina. 

 Agrostis vulgaris. 



Ground similar to this in respect of the abundance of Calluna, Racomi- 

 trium, and Empetrum, but differing from it in that the soil is a thick 

 peat, well drained by subterranean water-channels, is found on the 

 upper slopes of Kippure ; speaking generally, above the 1750 feet 

 contour line. This, however, we have mapped as Calluna ground, 

 this plant, though dwarfish, undoubtedly preponderating. To return 

 to the Racomiirium association in its more typical or wet facies. As 



