178 VEGETATION OF THE PEAK DISTRICT [CH. 



The vegetation of the roadsides, the footpaths, the banks 

 of streams, and the fringe of the heather moors is, in general, 

 of a grassy nature. In winter, it is possible to distinguish at 

 a distance of some miles the sinuous course of old footpaths and 

 bridlepaths by the contrast in colour which the bleached haulms 

 of the mat-grass {Nardus stricta) make with the surrounding 

 dark-coloured moorland vegetation. 



Ostenfeld (1908 : 887) states that the heather moors of the 

 Faeroes are always met with on slopes with a southern exposure : 

 this is not the case with regard to this association on the 

 Pennines; and the inference is probably to be made that in 

 the Faeroes, the association of heather moor is near its climatic 

 limit of distribution. 



On some of the more lowland of the heather moors, especially 

 in sheltered depressions, the bracken (Pteris aquilina) is very 

 abundant. It is possible that this plant is extending its range 

 on the moors. Wheldon and Wilson (1907 : 104) state that on 

 the heather moors of North Lancashire, " where grouse are a 

 prime consideration, the bracken is mowed periodically at con- 

 siderable expense, and the heather is then enabled to overcome 

 all rivals." 



There is not a great deal of human interference with nature 

 on the heather moors, although they are systematically fired by 

 the keepers every few years. The length of time which elapses 

 between the periods of firing varies locally, and determines the 

 height to which the heather grows. On Eyam Moor the heather 

 is fired about every four years, and therefore does not grow much 

 more than ankle high. On the remoter moors in upper Derwent 

 Dale, a period of eight to ten years elapses between the periods 

 of firing ; and the heather, on some of these moors, is ft-equently 

 more than knee deep. For one or two years after the heather 

 has been fired, the heather moor presents a desolate appear- 

 ance ; for the heather does not strongly reassert itself until at 

 least two years have elapsed. The first plant to become con- 

 spicuous after firing is the bilberry ( Vaccinium Myrtillus). The 

 latter frequently occurs as a partially etiolated plant under the 

 dominant heather, where its habit simulates that of Listera 

 cordata. In such circumstances, however, the bilberry rarely 

 flowers or fi-uits. The underground stems and buds of the 

 bilberry are frequently unharmed by the firing, even when the 



