94 



VEGETATION OF THE PEAK DISTRICT 



[CH. 



is a very thin forest of more or less dwarfed and stunted trees. 

 In nearly all cases, however, the scrub of this district appears 

 to consist of retrogressive forest communities, and only rarely, 

 as, for example, on certain fresh and newly formed soils beneath 

 cliflfs, of scrub progressing towards mature woodland. In the 

 retrogressive scrub, a number of the more hardy ground species 

 of wodds still persist, such as the wood-rush (Luzula pilosa), the 

 wood vetch ( Vicia sepium), Lathyrus montanum, the wood violet 

 (Viola Riviniana), the cow-wheat (Melaiupyruni montanum), 

 and the ubiquitous bracken (Pteris aquilina); but their 

 ultimate extinction, except perhaps in the case of the bracken, 

 as the woodland or scrub vegetation degenerates still further 

 towards grassland or heath or moor, appears certain. 



Several of these areas still retain the place-name " wood," 

 although now the name is most inappropriate ; but as such 

 areas occur within the primitive woodland zone, on more or 

 less sheltered slopes often near the head of the doughs 

 (cf. figure 12) and dales (cf figure 13), there need be no doubt 

 that the place-name really indicates the former nature of the 

 vegetation. It would appear to be true that, in districts which 

 are capable on climatic and edaphic grounds of supporting 

 woodland or true forest, the majority of the examples of open 

 scrub are to be regarded as degenerate woods and as retro- 

 gressive associations. A study of numerous examples of such 

 associations leads to the conclusion that the following succes- 

 sions have occurred and are still occurring in this district : 



Succession I 



Succession II 



Succession III 



Succession IV 



Oak and birch 

 woods on sand- 

 stone plateaux 



Scrub 



Siliceous grass- 

 land and heather 



Moors 



Oak and birch 

 woods on rocky 

 sandstone slopes 



Scrub 



Siliceous grass- 

 land (with Mo- 

 linia) 



Moors 



Oak and birch 

 woods on steep 

 shaly slopes 



Scrub 



Siliceous grass- 

 land 



Ash woods on 

 limestone slopes 



Scrub 



Calcareous 

 grassland 



