The habitats where common haircap~(Polytrichum commune) grows:

Altantic hazel wood
Atlantic oak wood
Beech wood
Blanket bog
Brownfield
Caledonian forest
Coastal floodplain grazing marsh
High montane heath and snow bed
Limestone pavement
Lowland dry acid grassland
Lowland fen
Montane dwarf shrub heath
Mountain ledge
Purple moor grass and rush pasture
Raised bog
Upland acid grassland
Upland acid rush pasture
Upland birch wood
Upland calcareous grassland
Upland dry heath
Upland rush pasture
Upland spring flush
Upland wet heath
Valley mire
Wet woodland
Wood pasture