108 VEGETATION OF THE PEAK DISTRICT [cH. 
this district, like it is, for example, on the Malvern Hills or on 
the Wicklow Hills (cf. Pethybridge and Praeger, 1905: 153, 
plates 7 and 8); but it occurs in patches in dry and fairly 
exposed localities. The rush (Juncus effusus and J. effusus forma — 
compactus), in damp places, and independently of conditions of 
shelter or exposure, is an abundant and characteristic associate. 
The bracken and the rush, in fact, are, in many places harvested 
by the upland farmers (see figures 15 and 16). 
The relationships of the various facies and aspects of 
the Nardus association may be indicated diagrammatically 
as follows :— 
NARDETUM STRICTAE 
nN 
: Facies of Facies of 
bs Agrostis vulgaris Deschampsia flexuosa Ey 
een a eee we ce 3 
3 Facies of Facies of Facies of © 
Ulex Galli Pieris aquilina Juncus effusus 
The bracken facies (see figure 15) and the rush facies 
(see figure 16) are very well developed in this district. For 
example, in ascending Longdendale (above Glossop), one meets 
with Nardus grassland on the hill-slopes. The bracken here 
varies from being a rare member of the association to a 
subdominant member. However, the general habitat conditions 
seem so very constant, and the bracken itself so very variable in 
amount in different parts of the association (even within quite 
small areas), that it seems impossible to regard the bracken 
as modifying the association any more than producing a facies. 
Towards the head of Longdendale, between Woodhead and 
Dunford Bridge, the bracken becomes less general; whilst the 
rush becomes a normal and an abundant member of the 
Nardus grassland. Such places are always ill-drained; and 
from them, the gorse and the bracken are invariably absent. 
The cotton-grass (Hriophorum angustifolvum) sometimes occurs. 
Such a Juncus facies of siliceous grassland must be distin- 
guished from the Juncus swamp (Juncetum effusi) described in 
Chapter VI. 
The bracken is one of the most accommodating of plants as 
regards its requirements. It is present in nearly all woods, 
except in the shadiest, dampest, and most calcareous places ; 
