Synonymy

Empetreto-Vaccinetum Burges 1951 p.p.; Vaccinium myrtillus-hchen heath Poore & McVean 1957; Empetrum-Xwhzn heath Poore & McVean 1957; Cladineto-Vaccinetum McVean & Ratcliffe 1962; Festuceto-Vaccinetum rhacomitrosum McVean & Ratcliffe 1962p.p.; Vaccinium myrtillus-Empetrum hermaphroditum nodum Huntley 1979; Festuceto-Rhacomitrietum lanuginosi (Birse & Robertson 1976) Birse 1980 p.p.; Carex bigelowii-Festuca vivipara Association (Birse & Robertson 1976) Birse 1980 p.p.

Constant species

Carex bigelowii, Deschampsia flexuosa, Vaccinium myrtillus, V. vitis-idaea, Racomitrium lanuginosum, Cetraria islandica, Cladonia arbuscula, C. uncialis.

Rare species

Loiseleuria procumbens, Kiaeria starkei.

Physiognomy

Like its heather-dominated counterpart, the Vaccinium myrtillus-Cladonia arbuscula heath consists essentially of a very low mat of sub-shrubs with an abundance of lichens, which again often mark out stands from a distance with a yellowish or grey-green tinge. Indeed, if anything, the lichens tend to be more extensive throughout this vegetation, and their dominance over the other components is more frequent and more extreme than in the Calluna-Cladonia heath. And, among the subshrubs, Calluna itself is uncommon overall: it increases in frequency in one sub-community but it is typically of low cover even there and of little structural importance, so the kind of wind-waved canopy associated with an abundance of flattened heather bushes is not usual here. The mat is still, however, very short, usually only 5-10 cm thick, but it is Vaccinium myrtillus that provides its most consistent element and, although this becomes sparse and noticeably lacking in vigour in more exposed situations, it is quite often abundant and a fairly regular co-dominant in what can be a dense and springy cover. V. vitis-idaea is somewhat less common and generally not so extensive and, in certain kinds of Vaccinium-Cladonia heath, it becomes distinctly patchy. V. uliginosum very occasionally shows local prominence, but overall it is scarce.

The other important sub-shrub in the community is Empetrum nigrum, almost always ssp. hermaphroditum and, in some of the vegetation included here (what McVean & Ratcliffe (1962) recognised as Cladineto-Vaccinetum), it becomes very frequent and often rivals or exceeds the Vaccinia in its cover. Alchemilla alpina can also be found, but it is nothing like so common or abundant as among the grassier stands of the Vaccinium-Deschampsia heath. The rare Arctic-Alpine Loiseleuria procumbens is very occasionally recorded, although neither it, nor the Arctostaphylos spp., play the sort of role here that they have in the Calluna-Cladonia or Calluna-A. alpinus heaths.