VII] MOORLAND ASSOCIATIONS 187 



The relationships of siliceous grassland and moorland may be 

 shown in the following table : 



Nardus grassland 



Dry facies 



(Deschampsia Jlexuosa or 

 Agrostis vulgaris abundant) 



Wet facies 



(Juncus ejfusus 



abundant) 



Nardus grassland with Nardus grassland with 



much heather much cotton-grass 



Heather moor Cotton-grass moor 



TRANSITIONAL ASSOCIATION OF HEATHER MOOR AND 

 COTTON-GRASS MOOR 



Where the boundary between a heather moor and a cotton- 

 grass moor is not marked by an escarpment, there is a wide, 

 level or gently sloping zone in which the heather and the 

 cotton-grass are co-dominant. These transitional areas are 

 marked on the vegetation maps by stippling red dots over 

 the colour used for the cotton-grass moor. A glance at the 

 map will show that such areas are abundant and widespread, 

 especially east of Derwent dale and south-west of Buxton. 

 On many of the latter moors, the cross-leaved heath (Erica 

 Tetralix) is very abundant. The majority of the associates 

 of the heather moor are absent ; and because of this fact, and 

 because of the deep wet peat which occurs, the transitional 

 moors have, on the whole, more in common with the cotton- 

 grass moors than with the heather moors. Hence the ground 

 colour chosen to indicate the transitional moors on the vegeta- 

 tion maps is that used for the cotton-grass moors. The usual 

 composition of the transitional moors (see figure 27) is given 

 in the following list : 



Sub-dominant 



i 

 Eriophorum vaginatum Calluna vulgaris 



Erica Tetralix 



Locally abundant 



Vaccinium Myrtillus Eriophorum angustifolium 



Rubus Chamaemorus Scirpus caespitosus 



Molinia caerulea 



