MOORLAND ASSOCIATIONS 251 
(usually dwarf), Salix repens, Polygala serpyllacea (heath- 
milkwort), Pedicularis sylvatica (lousewort), and Luzula 
campestris are frequently found. Other characteristic 
plants are: Potentilla Tormentilla, Galiwm saxatile, Pteris 
aquilina, Thymus Serpyllum, Achillea Millefoliwm, Hier- 
acium Pilosella, Campanula rotundifolia, Veronica offi- 
cinalis, Huphrasia officinalis, Teucrium Scorodonia, Rumex 
Acetosella, and various species of Rubus. 
Nardus stricta-Association.—On poorer soils, especially 
in the sub-alpine zone (1,000 to 2,000 feet), Nardus stricta 
(matgrass), which is found sparingly at lower levels, 
becomes dominant. Festuca ovina, Aira flexuosa, and 
Agrostis vulgaris also occur, with Molinia cerulea in the 
wetter parts. Calluna is usually less frequent than in the 
preceding association, but Vaccinium Myrtillus is more 
abundant. Potentilla Tormentilla, Galium saxatile, Rumex 
Acetosella, and Luzula campestris are still very common, 
and mixed with these are plants characteristic of high 
altitudes—e.g., Juncus squarrosus, Lycopodium Selago, and 
L. clavatum. 
Molinia-Bog.—Where the drainage is very bad and the 
soil wet, Nardus stricta is displaced by Molinia cerulea. 
‘ Associated with the latter are many bog-plants—e.g., 
Juncus effusus, J. conglomeratus, Eriophorum vaginatum 
(cotton-grass), Aira cespitosa, Narthecium ossifragum, 
Hydrocotyle vulgaris, Vaccinium Oxycoccus, Erica Tetralix, 
Rhynchospora alba, Carex (C. Goodenowit and other 
species), Sphagnum, etc. Above 2,000 feet the Molinia-bog 
passes over into cotton-grass moor. 
Summit-Heath.—At high altitudes (1,500 to 2,500 feet) 
a summit-heath, intermediate in character between the 
alpine-pasture and the Vaccinium-moor, is developed. 
It consists chiefly of Nardus stricta and Juncus squarrosus, 
with Vaccinium Myrtillus sometimes sharing dominance. 
A few plants found at lower levels still persist—e.g., Avra 
flexuosa, Potentilla Tormentilla, Galium saxatile, Huphrasia 
officinalis, and Luzula campestris—but alpine plants are 
frequent—e.g., Alchemilla alpina, Lycopodium Selago, 
L. clavatum, Empetrum nigrum (crowberry), Vaccinium 
Vitis-idea (cowberry), Antennaria dioica, and in the 
wetter parts Rubus Chamemorus, Vaccinium uliginosum 
(mountain blaeberry), and Hriophorum. 
