Synonymy

Rhacomitreto-Callunetum McVean & Ratcliffe 1962, Birks 1973 ; Dwarf mountain heaths Gimingham 1972 p.p.; Calluna vulgaris-Arctostaphylos uva-ursi nodum Prentice & Prentice 1975 p.p.; Alectorio-Callunetum, Agrostis canina ssp. montana subassociation Birse 1980 p.p.

Constant species

Calluna vulgaris, Deschampsiaflexuosa, Hypnum cupressiforme s.l., Racomitrium lanuginosum, Cladonia arbuscula, C. uncialis.

Rare species

Arctostaphylos alpinus, A. uva-ursi, Loiseleuria procumbens.

Physiognomy

The Calluna vulgaris-Racomitrium lanuginosum heath consists essentially of a dwarfed sub-shrub mat, with Calluna vulgaris usually predominating as in the Calluna-Cladonia heath, but with Racomitrium lanuginosum occupying the prominent role which lichens have in that community. As there, the cover of woody plants is typically far from complete, with the heather, severely wind-trimmed to prostrate bushes just a few centimetres thick, often occupying less than half of the ground. Other sub-shrubs generally play a subordinate part, but a number are quite common, sometimes showing local abundance, partly replacing Calluna or supplementing its cover, and helping to distinguish the different subcommunities. The most frequent of these woody associates throughout is the Arctic-Alpine Empetrum nigrum and, again as in the Calluna-Cladonia heath, the two sub-species tend to characterise opposite extremes of the altitudinal range of this community, with ssp. nigrum being preferentially common and moderately abundant towards lower levels, ssp. hermaphroditum largely confined to the higher. But Erica cinerea is frequent too, much more so than in the continental Calluna-Cladonia heath and especially at lower altitudes where, with Arctostaphylos uva-ursi and A. alpinus, it helps give the Arctostaphylos sub-community its distinctive character. Both species of bearberry can show quite high covers here and this kind of heath includes much of the vegetation in north-west Scotland where these two rare Arctic-Alpines occur together. Another rarity occasionally represented in the community is Loiseleuriaprocumbens, and scattered throughout are scarce records for Juniperus communis, generally clearly of ssp. nana. Vaccinium myrtillus is never more than occasional and typically present as sparse shoots, and V. vitis-idaea and V. uliginosum are rare.

Among the open patchwork of flattened bushes, other vascular associates are few and far between, with usually scattered and stunted individuals, but this element of the flora can be a little more varied than in the Calluna-Cladonia heath.