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 Eriophorum vagi- 

 natum (Eriophoretum vaginati). 



3. Bilberry moor. Association of Vaccinium Myrtillus 

 (Vaccinietum myrtilli). 



4. Retrogressive moors whose chief constituents are the 

 bilberry, the crowberry (Empetrum nigrum), and the cloudberry 

 (Rubus Chamaemoriis). 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 (1904 a: 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. papil- 

 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, Eriophorum angustifolium, 

 Garex 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, S. cuspidatum, S. recurvum, 

 S. inundatum, S. tenellum. 



