166 VEGETATION OF THE PEAK DISTRICT [CH. 
CLASSIFICATION OF MOORLAND ASSOCIATIONS 
The moorland plant associations of the district may be 
arranged and designated as follows :— 
1. Heather moor. Association of Calluna vulgaris (Cal- 
lunetum vulgaris). 
2. Cotton-grass moor. Association of Hriophorum vagi- 
natum (Eriophoretum vaginati). 
38. Bilberry moor. Association of Vaccinium Myrtillus 
(Vacciniétum myrtill1). 
4. Retrogressive moors whose chief constituents are the 
bilberry, the crowberry (Empetrum nigrum), and the cloudberry 
(Rubus Chamaemorus). Locally, extensive patches of bare peat 
occur. 
5. Transitional moors of heather and cotton-grass. 
6. ‘Transitional moors of heather and bilberry. 
7. Transitional areas of heather and siliceous pasture. 
8. Transitional areas of cotton-grass and siliceous pasture. 
In other parts of the British Isles, the following additional 
moorland plant associations have been recognised. 
9. Sphagnum moor. Sphagnum moors are mapped 
by Lewis (1904a: 325). They are also described for north 
Lancashire by Wheldon and Wilson (1907: 102) who state 
that this “upland Sphagnum association” has for its dominant 
species Sphagnum recurvum, and that this is occasionally 
accompanied by other bog mosses, such as S. nitens, S. papzl- 
losum, and S. rubellum, and still more frequently by Polytri- 
chum commune. Frequent members of this association, though 
usually marginal or very subordinate, are Viola palustris, Vac- 
cinium Oxycoccus, Juncus effusus, Hriophorum angustifolvum, 
Carex echinata, C. canescens, and locally Rhyncospora alba. One 
of the Sphagnum moors mapped by Lewis (op. cit.) has more 
recently been visited by the members of the Yorkshire Natu- 
ralists’ Union (see The Naturalist, 1910: 265 and 313), who 
reported, in addition to many other mosses and Hepatics, the 
following species of Sphagnum :— 
S. rubellum, S. acutifolium, S. subnitens, 8S. cuspidatum, S. recurvum, 
S. inundatum, S. tenellum. 
