Nardetum strict^ 133 



and, in early summer, the tall, purple scapes of this grass 

 are very conspicuous. There seems little doubt, however, 

 that the Nardetum of the southern Pennines is ecologically 

 identical with that of the Wicklow Hills' and with that 

 of the northern Pennines^, even though the silver hair- 

 grass is not included in the lists of the association by 

 the authors mentioned. 



The two grasses (Nardus stricta and Deschampsia 

 jiexuosa) of the association remain abundant or even 

 dominant up to about 1500 feet (457 m.). Below about 

 1250 feet (381m.), the common bent grass (Agrostis 

 tenuis = A. vulgaris) is often very abundant; and, in the 

 late summer months, its delicate and purple panicles may 

 colour a whole hillside. As lower altitudes are approached, 

 this species becomes increasingly abundant at the expense 

 of the mat-grass, and associated species become more and 

 more abundant. The sheep's fescue-grass (Festuca ovina) 

 is also often associated, and this species sometimes forms 

 plant-societies or facies. 



The shady hill-slopes which encircle the upper Bdale 

 valley afford an extensive and continuous expanse of the 

 typical Nardetum. On the north of this upland valley 

 are the slopes of the Peak, on the south the slopes of 

 the Mam Tor range, and on the west the slopes of 

 the Colborne moors. In the sheltered Grindsbrook 

 clough, the bracken (Pteris aquilina) asserts itself very 

 strongly : the small furze ( Ulex Gallii) occurs in small 

 patches here and there, and the springs of water on the 

 hillsides are marked by clumps of the common rush 

 {Juncus effusus). 



The last three species give to the association very 

 different aspects or facies. The bracken, where the soil is 

 dry and the locality sheltered, sometimes occurs in ex- 

 tensive sheets, masking the otherwise dominant grasses. 



1 Pethybridge and Praeger, 1905. 



2 Lewis, 1904. 



