Synonymy

Schoenetum Newbould 1960; Roydon Common Zone 5a Daniels & Pearson 1974p.p.; Schoenetum nigricantis Ivimey-Cook et al. 1975; Schoeno-Juncetum subnodulosi ericetosum (Allorge 1922) Wheeler 1980Z? p.p.

Constant species

Anagallis tenella, Erica tetralix, Molinia caerulea, Narthecium ossifragum, Schoenus nigricans, Aneura pinguis, Campylium stellatum, Scorpidium scorpioides, Sphagnum auriculatum, S. subnitens.

Physiognomy

The Schoenus nigricans-Narthecium ossifragum mire includes mildly calcicole Schoenus vegetation of southwest lowland Britain which cannot readily be integrated in the Schoenetum. As in that community, Schoenus is usually a strong dominant here, and its grey-green, semievergreen foliage often enables stands to be picked out at a distance from their usual context of brownor straw-coloured Sp/zagnwm-dominated vegetation or heaths. And the tussock habit of the plant, with its robust rootstocks crowned by densely-caespitose clumps of shoots (Sparling 1962a, 1968), again gives the vegetation its distinctive structural character, with stools packed at varying densities and separated by systems of runnels. The tussock tops provide their characteristic niche for calcifuges but, in this community, the calcicolous element is confined to areas of close contact with the irrigating waters, other distinctive plants making an appearance around the bases of the tussocks.

Species occurring frequently in both communities are few in number and the most obvious is Molinia caerulea, which is generally abundant here, reinforcing the tussocky character of the vegetation. Typically, mixtures of Schoenus and Molinia cover the bulk of the ground without any Juncus subnodulosus, a species that is quite often co-dominant in the Schoenetum. Indeed, no other rushes or sedges of medium stature play an important role in this community: there is occasionally some J. acutiflorus, but it is not usually abundant. Other elements conspicuous by their absence are the various small sedges and other herbs that commonly line the runnels of the Schoenetum and provide much of its calcicolous stamp, and the taller mesophytic plants that give that community much of its colour: of these only Carex panicea and C. demissa are occasionally found, and sometimes Dactylorhiza incarnata ssp. pulchella.

Among other vascular plants represented here, only Anagallis tenella provides a floristic link between the two communities.