Synonymy

Juniperus-Arctostaphylos sociation Poore & McVean 1957; Juniperetum nanae McVean & Ratcliffe 1962 p.p.; Juniperus nana nodum Birks 1975 p.p.

Constant species

Calluna vulgaris, Deschampsia flexuosa, Erica cinerea, Juniperus communis ssp. nana, Potentilla erecta, Scirpus cespitosus, Hypnum cupressiforme s.l., Racomitrium lanuginosum, Pleurozia purpurea, Cladonia uncialis.

Rare species

Arctostaphylos alpinus, A. uva-ursi, Loiseleuriaprocumbens, Herbertus borealis, H. stramineus, Plagiochila carringtonii.

Physiognomy

Prostrate juniper referable to Juniperus communis ssp. nana occurs as an occasional, sometimes with modest local abundance, in a variety of dwarfed sub-shrub heaths in Britain, notably in the Calluna-Racomitrium and Calluna-A. alpinus types. But in the Calluna-Juniperus heath, it is more or less consistently dominant in the sub-shrub mat and accompanied by a small but distinctive element of oceanic hepatics.

The mat is generally less than 10 cm thick and often severely wind-pruned to much less than this, fairly continuous in the best developed stands, though more fragmentary over erosion surfaces and where there has been burning, to which the dwarf juniper is very sensitive (McVean 196\b, Poore & McVean 1957). A number of other sub-shrubs are well represented, with Calluna vulgaris and Erica cinerea being especially frequent, and the former often fairly abundant, though not generally assuming dominance. Arctostaphylos uva-ursi and A. alpinus are somewhat less common and usually of low cover and Empetrum nigrum spp. hermaphroditum occurs occasionally. Vaccinium myrtillus and V. uliginosum are scarce and the community provides an occasional locus for Loiseleuria procumbens.

Vascular associates are typically rather few in number and occur as scattered and often stunted individuals among the mat. Deschampsia flexuosa, Scirpus cespitosus and Potentilla erecta are constant, with Huperzia selago, Solidago virgaurea (in its so-called var. cambrica), Dactylorhiza maculata, Polygala serpyllifolia, Succisa pratensis and Antennaria dioica more occasional. Carex panicea, C. pilulifera, C. bigelowii, Festuca vivipara and Nardus stricta can also sometimes be found and, more unusually, there can be some Thymus praecox.

In some stands, the cryptogam flora seems little different from other kinds of dwarfed sub-shrub heath, as in some of the semi-degraded samples of Poore & McVean (1957) and of McVean & Ratcliffe's (1962) lichenosum and, indeed, such vegetation where the juniper cover is lower than usual is best shifted into other communities.