184 VEGETATION OF THE PEAK DISTRICT [CH. 



fifteen feet (305 to 457 cm.) in depth, and rarely less than five 

 feet (152 cm.). On rare occasions, as in local hollows and 

 swamps, it may reach a depth of twenty feet (610 cms.) or more. 

 The peat is usually saturated and frequently supersaturated 

 with water, although the superficial layer occasionally becomes 

 very dry in summer. 



Over many parts of the higher moors, Eriophorum vagin- 

 atum is the dominant plant ; and, wherever this plant occurs 

 in quantity, the depth of the peat is being added to year 

 by year and denudation of the peat is not taking place. At 

 the present time, Eriophorum vaginatum probably forms peat 

 at a more rapid rate and over wider stretches of English moor- 

 lands than any other plant; and the statement, occasionally 

 met with, that peat formation is a phenomenon of the past and 

 not of the present is incorrect. 



Bog-mosses (Sphagnum spp.) are even rarer on the cotton- 

 grass moors than on the heather moors, though a contrary 

 opinion has gained credence ; and the erroneous view is still 

 met with that the dominance of Sphagnum is a necessary 

 condition of peat formation. As a matter of fact. Sphagnum 

 is invariably absent from the peat of true fens, and is by no 

 means a necessary constituent of the peat of moors. One may 

 walk many miles over the moors of this district without seeing 

 any trace of Sphagnum ; and one may examine many sections of 

 the peat of the district without finding any trace of its remains. 



The cotton-grass moors are extensive, dreary, and monotonous. 

 Eriophorum vaginatum is frequently not merely the dominant 

 but the only vascular plant which occurs. In late summer and 

 early autumn, the dead green hue of the shoots of the cotton- 

 grass is scarcely relieved by any other touch of colour. In late 

 autumn and throughout the winter, the shoots fade to dull 

 red ; and the vegetation then presents a most forbidding aspect. 

 A little life is infused into the area in April and May, when the 

 dusky brown florets make their appearance ; but only in June, 

 when the pure white fruits of the cotton-grass appear like 

 suspended snow-flakes, is the cotton-grass moor attractive to 

 the eye (see figure 26). 



The monotony of the cotton-grass moor is, however, relieved 

 by certain physiographical features to which the vegetation 

 responds. A sandstone escarpment or outcrop causes a decrease 



