M11 - Carex Demissa-Saxifraga Aizoides Mire Carici-Saxifragetum Aizoidis Mcvean & Ratcliffe 1962 Emend.

Summary

Synonymy

Carex demissa-C. panicea nodum Poore 1955a p.p.; Cariceto-Saxifragetum aizoidis McVean & Ratcliffe 1962, Prentice & Prentice 1975; Carex-Saxifraga aizoides nodum Birks 1973, Huntley & Birks 1979; Pinguiculo-Caricetum dioicae Jones 1973 p.p.; Saxifraga aizoides-Juncus triglumis nodum Huntley 1979; Caricetum atrofusco-vaginatae Dierssen 1982; Schoenus ferrugineus stands Wheeler et al. 1983 p.p..

Constant species

Carex demissa, C. panicea, C. pulicaris, Juncus articulatus, Pinguicula vulgaris, Saxifraga aizoides, Aneura pinguis, Blindia acuta, Bryum pseudotriquetrum, Campylium stellatum, Drepanocladus revolvens.

Rare species

Alchemilla filicaulis ssp. filicaulis, Carex atrofusca, C. microglochin, C. vaginata, Equisetum variegatum, Juncus alpinus, J. biglumis, J. castaneus, Kobresia simpliciuscula, Salix reticulata, Schoenus ferrugineus, Calliergon trifarium, Meesia uliginosa.

Physiognomy

The Carici-Saxifragetum aizoidis is typically an open community in which rich mixtures of small sedges, other herbs and bryophytes occur among water-scoured runnels with much exposed silt and rock debris on sometimes steeply-sloping ground. Typically, there is no single vascular dominant, though sedges and other monocotyledons almost always compose an important element of the vegetation, providing a strong floristic link with the Pinguiculo-Caricetum. Thus, Carex demissa, C. panicea and C. pulicaris are very frequent almost throughout, and each can attain moderately high cover (usually less than 25%), and C. flacca and C. dioica become common in particular variants, though not generally with any abundance. Juncus articulatus is also a constant, Eriophorum angustifolium occurs frequently and, at lower altitudes, Eleocharis quinqueflora becomes very characteristic. In some such stands, the local dominance of Schoenus nigricans (or, in some Perthshire localities, S. ferrugineus), together with some Eriophorum latifolium, can accentuate the similarities between the two communities.

In comparison with the Pinguiculo-Caricetum, however, Carex lepidocarpa and C. hostiana are much less common, and C. nigra and C. echinata are likewise rather scarce. And, at higher altitudes, an Arctic-Alpine component becomes prominent with Juncus triglumis attaining constancy and Tofieldia pusilia increasing in frequency. Here, too, the community provides an occasional locus for Juncus biglumis, J. castaneus, Carex atrofusca, C. microglochin and, more unusually, C. vaginata, and for Kobresia simpliciuscula.

Grasses are typically of low cover, though a variety of species can be found. Festuca ovinalvivipara is common throughout and Agrostis stolonifera occurs occasionally.