vil] 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 tenuis) alternating with patches of heathy 
dwarf shrubs, such as heather (Calluna vulgaris), bilberry ( Vac- 
cuntum 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 (Vaccinium Vitis-cdaea) 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 
VY. 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 
