Synonymy

Callunetum arenosum Tansley 1911 p.p:, Callunetum Farrow 1915, Watt 1936; Callunetum arenicolum Tansley 1939 p.p.

Constant species

Calluna vulgaris, Festuca ovina, Dicranum scoparium, Hypnum cupressiforme s.l.

Physiognomy

The Calluna vulgaris-Festuca ovina heath is a heatherdominated community, very poor in vascular associates, though sometimes showing a modest diversity among the bryophytes and, more especially, the lichens. Calluna vulgaris is usually the only woody species present and invariably the most abundant. More particularly, Erica cinerea, Ulex minor and U. gallii, which become important constituents of the sub-shrub component of dry heaths further to the south and west, are largely excluded here. They sometimes figure in stands on or near the East Anglian coast, and the first two can occasionally be found in the few stations for the community south of the Thames, but the general scarcity of these species furnishes a good diagnostic criterion, provided that it is remembered that they can be locally eliminated from richer heath types to produce the kind of virtually pure Calluna that is usual here. Another general absentee is Erica tetralix'. this becomes increasingly prominent through the whole range of wet and humid heaths towards south-west Britain but is very scarce here and strictly limited to those rather unusual situations where there is a transition to soils with impeded drainage. Ulex europaeus is likewise uncommon, though it can become locally abundant where there has been some disturbance, not necessarily recent, as along trackways or around the margins of plantations.

However, although it is Calluna which gives this community its distinctive stamp, the cover and height of the canopy are very variable. This affects not only the gross appearance of the vegetation, which can have a canopy of living heather anything between 10 and 100 cm tall, covering 50-100% of the ground, but it also has a controlling influence on the variety, abundance and distribution of the associated flora, which is for the most part confined to areas between the Calluna clumps and to the centre of those bushes which are collapsing with age or showing early regeneration from the stools or seed.