vil] MOORLAND ASSOCIATIONS 167 
10. Cotton-grass moor. Association of Hriophorum 
angustifoliwm (Eriophoretum angustifolii). 
11. Scirpus moor. Association of Sczrpus caespitosus 
(= Trichophorum caespitosum) (Scirpetum caespitosi). 
These two associations are described by Pethybridge and 
Praeger (1905: 166—7), and occur on the Wicklow mountains 
south of Dublin. In certain Scottish localities also, namely, 
in the north-western Highlands, in the Hebrides, and in the 
Shetlands, “Scirpus caespitosus dominates the most character- 
istic associations. - In N.W. Sutherland, the flat, basaltic plateau 
of northern Skye, and the valley floors and gently sloping hillsides 
of Shetland, this type remains dominant over many hundred 
square miles.... In the western portion of N. Uist, the Scirpus 
caespitosus association extends over hills of low elevation and 
broad shallow valleys” ([F. J. Lewis, in] The New Phytologist, 
1908 : 257). Scirpus moors resemble the cotton-grass moors and 
heather moors of the Pennines in the comparative scarcity of 
bog-mosses (Sphagnum spp.). 
12. Rhacomitrium moor. Association of Rhacomitrium 
lanuginosum (Rhacomitriétum lanuginosi). Pethybridge and 
Praeger (1905: 167) describe a modification of the heather moor 
and the Scirpus moor brought about by the local dominance 
of a species of woolly moss (Racomitrium lanuginosum). The 
association of Rhacomitriwm lanuginosum would appear to be 
fairly widespread in western Scotland; and “ Rhacomitrium 
bogs” in Caithness are described by Crampton (1911: 55). 
All the above associations and societies occur on peat which 
is marked by acidic waters, and by a low soluble mineral- 
content, especially by a low lime-content. The plant formation 
of such a habitat has been termed an Oxodion (Moss, 19100: 
43); and its described chief associations in the British Isles may 
be designated as follows (cf. Moss, loc. cit.) :— 
Oxodion Calluneti-vulgaris 
Oxodion Eriophoreti-vaginati 
Oxodion Vacciniéti-myrtilli 
Oxodion Sphagneti-recurvi 
Oxodion Eriophoreti-angustifolii 
Oxodion Scirpeti-caespitosi 
Oxodion Rhacomitriéti-lanuginosi 
