A locally abundant or co-dominant drawf srub in heathland with Calluna and Erica cinerea, or Ulex spp., often with calcicolous herbs, over ultrabasic rocks (serpentine and gabbro); also found on moist gley soils. Seedlings and plantlets can be frequent, but often die of drought; older plants regenerate from the base after winter burning. Lowland.
In Britain, about one third of the heaths containing E. vagans were lost between 1908 and 1980. The remainder now have statutory protection, and the distribution seems stable. In Co. Fermanagh E. vagans is treated here as native but may be a prehistoric introduction.
Oceanic Southern-temperate element.
Light (Ellenberg): 8
Moisture (Ellenberg): 6
Reaction (Ellenberg): 4
Nitrogen (Ellenberg): 1
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 6
July Mean Temperature (Celsius): 15.5
Annual Precipitation (mm): 1047
Count of 10km squares in Great Britain: 6
Count of 10km squares in Ireland: 1
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.07
RDB Species Accounts
Erica vagans L. (Ericaceae)
Cornish heath, Grug Cernyw
Status in Britain: LOWER RISK - Near Threatened.
Status in Europe: Not threatened. Endemic.
In Britain, E. vagans occurs only on the Lizard peninsula, where it is almost restricted to four hectads. It is not merely abundant in many localities, but is co-dominant in species-rich heathlands over large areas of the plateau and in sheltered rocky coastal valleys and slopes on the ultra-basic rocks, serpentine and gabbro. It is co-dominant with Ulex europaeus and U. gallii on brown earth soils (pH 6-7) on sheltered slopes from near sea level to 100 metres (Coombe & Frost 1956a), together with a wide spectrum of other vascular plants, including Calluna vulgaris, Erica cinerea, Genista pilosa, Viola lactea and basiphiles such as Filipendula vulgaris and Pimpinella saxifraga. In broad shallow valleys over much of the Lizard plateau, E. vagans is co-dominant with Molinia caerulea and Schoenus nigricans on silty clay, and neutral to slightly acid, gley soils overlying serpentine and gabbro. This 'Tall Heath' (Coombe & Frost 1956a) is also species-rich, and includes Carex pulicaris and Erica tetralix. E. vagans is intolerant of extreme exposure to salt-laden winds and therefore rarely occurs in the cliff-top Calluna - Scilla verna heaths.
It survives at one site on palaeozoic shales inland in West Cornwall, but was quarried away on a basic igneous outcrop in East Cornwall. It is absent from acidic but fertile schists fringing the serpentine, and from expanses of Ulex gallii - Agrostis curtisii heaths on deep acidic silty loess which overlies both serpentine and gabbro on level areas of the plateau (Coombe & Frost 1956b; Staines 1984; Rodwell 1991).
E. vagans is a rather straggly glabrous shrub up to 80 cm tall, producing its pale pink or white flowers from July to September. Seedlings and plantlets are locally frequent but often die of drought (most notably, for instance, in 1949, 1955 and 1976). Bushes rarely die of old age, though about 50 annual growth rings were counted on one dead bush in an exceptionally old stand (which was burnt in 1955). Propagation by shoot-tip cuttings is easy, and it regenerates from the base after controlled winter burning.
About one-third of the Lizard heathlands were lost between 1908 and 1980 (J.J.Hopkins in Turpin 1984), and both the 'Tall Heath' and the 'Mixed Heath' vegetation have been much modified by turf-paring and repeated burning. However, large areas of the E. vagans heath which remain now have statutory protection, and the overall population of E. vagans is likely to be stable. Limited areas are grazed by cattle in the out-fields of a few farms.
The Irish population of (white-flowered) E. vagans in County Fermanagh is perhaps a prehistoric introduction ('archaeophyte') (Nelson & Coker 1974). E. vagans otherwise occurs only in western and central France and northern Spain, sometimes on calcareous soils with, for example, Cornus sanguinea.
D. E. Coombe
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.
Atlas text references
1995. Flora dels Països Catalans, III. Pirolàcies-Compostes.
1988. The Irish Red Data Book. 1. Vascular Plants.
1962. La flore atlantique européenne. Documents pour les cartes des productions végétales serie Europe-Atlantique, vol. 1.
1999. British Red Data Books. 1. Vascular plants, edn 3.