Synonymy

Saxifragetum aizoidis McVean & Ratcliffe 1962, Birks 1973; Mixed Saxifrage facies McVean & Ratcliffe 1962; Saxifraga aizoides-Festuca-Deschampsia nodum Huntley 1979; Saxifraga aizoides-Tussilago farfara nodum Huntley 1979.

Constant species

Alchemilla alpina, A. glabra, Carexpulicaris, Deschampsia cespitosa, Festuca ovinalvivipara, F. rubra, Pinguicula vulgaris, Polygonum viviparum, Ranunculus acris, Saxifraga aizoides, S. oppositifolia, Selaginella selaginoides, Thalictrum alpinum, Bryum pseudotriquetrum, Ctenidium molluscum.

Rare species

Alchemilla filicaulis ssp. filicaulis, Carex capillaris, Cerastium alpinum, Cystopteris montana, Epilobium alsinifolium, Juncus biglumis, Oxytropis campestris, Poa alpina, P. glauca, Potentilla crantzii, Polystichum lonchitis, Salix lapponum, Sibbaldia procumbens, Barbilophozia quadriloba, Hylocomiumpyrenaicum, Hypnum baumbergeri, H. callichroum.

Physiognomy

The Saxifraga aizoides-Alchemilla glabra community forms highly distinctive banks of vegetation disposed over steep, rocky or earthen slopes. Typically, there is a dripping wet carpet of plants, sometimes just a decimetre or so thick, but growing very luxuriantly, in which Saxifraga aizoides is generally the most abundant plant, looking especially striking in summer with its bright yellow flowers. S. oppositifolia is constant too and, though it is usually found in small clumps, stands can be seen in which it attains co-dominance with S. aizoides'. McVean & Ratcliffe (1962) separated these off into a ‘mixed Saxifrage facies’ but, with further sampling, it is not really possible to justify this. S. hypnoides also occurs quite commonly and S. stellaris very occasionally, but neither has high cover.

The other abundant element in the vegetation consists of grasses, though neither these nor the sedges of the community ever attain the prominence here that is characteristic of the flushed grasslands or mires in which S. aizoides is important. Nonetheless, Deschampsia cespitosa, Festuca rubra and F. ovinalvivipara are all very frequent, and the first two sometimes make up quite a proportion of the sward. Also common, though not so extensive, are Anthoxanthum odoratum and Agrostis capillaris, with Nardus stricta and Agrostis canina occurring occasionally. The community provides a locus, too, for the rare Arctic-Alpine grasses Poa alpina and the particularly handsome P. glauca, a taxon now subsuming P. balfouri (Tutin et al. 1980).