Scientific name Molinia caerulea – Schoenus nigricans bog/heath
Common name Purple Moor-grass – Black Bog-rush bog/heath
Community code HE4C


HE4C: Molinia caerulea – Schoenus nigricans bog/heath     HE4C: Molinia caerulea – Schoenus nigricans bog/heath     HE4C map: Molinia caerulea – Schoenus nigricans bog/heath

Download full pdf synopsis: HE4C



This assemblage is dominated by a mixture of Schoenus nigricans and Molinia caerulea which lend it a grassy and tussocky appearance. Dwarf shrub cover is low although both Calluna vulgaris and Erica tetralix are constants here, as is Potentilla erecta. Frequent species in the field layer comprise Eriophorum angustifolium, Polygala serpyllifolia, Narthecium ossifragum and Drosera rotundifolia. The bryophyte layer is somewhat sparse with the following species frequent but none constant: Racomitrium lanuginosum, Hypnum jutlandicum, Odontoschisma sphagni, Sphagnum papillosum and the vermicular Pleurozia purpurea.



This is a community of lowland blanket bogs and wet heaths on the lower slopes of hills and mountains.  Soils are wet, acidic and infertile ombrogeneous peats.



Two sub-communities are described. The Myrica gale – Sphagnum papillosum sub-community (HE4Ci) occurs in flushed or boggy situations and has a higher frequency of Sphagnum species than the Racomitrium lanuginosum – Pleurozia purpurea sub-community (HE4Cii) where Cladonia species are more prevalent.


Similar communities

The BG1C Schoenus nigricans – Eriophorum angustifolium bog is a rather degraded Schoenus bog with lower overall plant cover than HE4C. The BG2D Erica tetralix – Schoenus nigricans bog is more diverse than HE4C with less dominance of Schoenus and Molinia. In both those other communities, Rhynchospora alba is a constant, unlike in HE4C, which is more heathy and less boggy in character.


Conservation value

This is on average a fairly species-poor peatland community. Most examples will qualify as either EU HD Annex I habitat 4010 Wet heath or habitat 7130 Blanket bog (active)*.



Where it occurs as heathland this community often forms parts of commonages and is usually used as rough grazing land (typically for sheep); overgrazing may be a problem. Burning may be periodically used across large areas to suppress the dwarf shrubs and encourage grass growth. Where it occurs as bog it is often used for turf-cutting, either by hand or machine. The other main threats are afforestation and agricultural improvement.