VII] MOORLAND ASSOCIATIONS 181 



TRANSITIONAL ASSOCIATION OF HEATHER MOOR AND 

 SILICEOUS GRASSLAND 



Some of the uncultivated areas are intermediate between 

 heather moor and siliceous grassland. Most commonly in such 

 places one finds patches of rough grass, such as the mat-grass 

 (Nardus stricta), silver hair grass (Deschampsia flexuosa), and 

 bent grass (Agrostis tennis) alternating with patches of heathy 

 dwarf shrubs, such as heather (Calluna vulgaris), bilberry (Vac- 

 cinium Myrtillus), and the fine-leaved heath (Erica cinerea). 

 At other times, one finds a closer but dwarfed growth of the 

 heathy dwarf shrubs but with a much larger proportion of the 

 grasses than occurs on heather moor. It is rather rare to 

 find the cowberry (Vacdnium Vitis-idaea) and the crowberry 

 (Empetrum nigrum) in this transitional area ; but the combina- 

 tion does occur. The soil is not peaty, although it contains 

 more humus (of the acidic type) than is found on siliceous 

 grassland. Vegetation of this nature is found not infrequently 

 on the lower sandstone plateaux; and it is quite uncommon 

 on the steep, shaly slopes. This is a subordinate association 

 and probably of progressive nature; and it is here regarded 

 as a stage in the succession from siliceous grassland to heather 

 moor. On the vegetation maps, it is indicated by stippling the 

 red colour used for heather on the colour used for siliceous 

 grassland. 



Plants from the neighbouring plant associations and even 

 plants from the cultivated area invade the heather moor, 

 especially along the footpaths and streamsides; and, in such 

 places, the following species sometimes occur mixed with the 

 heather : 



Urtica dioica (local) Hieracium Pilosella 



Rumex Acetosa Taraxacum officinale 



Ranunculus bulbosus var. maculiferum 



Viola Riviniana Agrostis tenuis 



V. lutea (local) (=A. vulgaris) 



Polygala serpyllacea Aira praecox 



Heracleum spondylium (local) Triodea decumbens 



Plantago lanceolata Luzula campestris 



Achillaea Millefolium L. vernalis 



Bellis perennis (^L. pilosa) 

 Hypochaeris radicata 



