A low, usually prostrate, shrub growing mainly on rocky cliff-tops in maritime grassland or heath. It also grows in limestone grassland in Brecon, on rock ledges in the Cadair Idris range, and formerly on dry heaths in S. England. Generally lowland, but reaching 710 m on Cadair Idris (Merioneth).
All G. pilosa sites on inland heaths have been lost through agricultural improvement or lack of management. The Breckland populations had become extinct by 1866 but the last inland site, in Sussex, survived until 1977 or perhaps 1980. Elsewhere, the distribution and populations seem stable.
European Temperate element.
Light (Ellenberg): 8
Moisture (Ellenberg): 5
Reaction (Ellenberg): 4
Nitrogen (Ellenberg): 1
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 5
July Mean Temperature (Celsius): 15.6
Annual Precipitation (mm): 1011
Count of 10km squares in Great Britain: 23
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.26
RDB Species Accounts
Genista pilosa L. (Fabaceae)
Hairy greenweed, Aurfanadl Blewog
Status in Britain: LOWER RISK - Near Threatened.
Status in Europe: Not threatened. Endemic.
In Britain, G. pilosa occurs in a range of habitats. Most of its sites are coastal dwarf-shrub heaths and cliffs, but it also occurs inland in grasslands and on mountain rocks and crags. The substrate is usually well-drained acidic sandy or gravelly soil on heaths, but it occurs locally on rendzinas and loams overlying limestone and serpentine. On coasts, it may be major component in heath and grassland on both flat and steeply-sloping sites, together with Armeria maritima, Calluna vulgaris, Erica cinerea, Festuca ovina, Hypochaeris radicata, Pedicularis sylvatica, Plantago maritima and Scilla verna. On Cader Idris, most colonies grow on precipitous south- to west-facing crags at an altitude of 480-710 metres, where they are inaccessible to sheep. Associated species include Calluna vulgaris, Carex pilulifera, Erica cinerea, Festuca ovina, Solidago virgaurea, Vaccinium myrtillus and Racomitrium lanuginosum. The Breconshire colonies are in a mosaic of grassland and limestone pavement, though the suite of associated species, including Anthoxanthum odoratum, Carex flacca, Deschampsia flexuosa, Helictotrichon pratense, Potentilla erecta, Thymus polytrichus, Vaccinium myrtillus and Viola riviniana, seems to indicate that it grows on both acid and basic soils there. In southern England, it occurred on dry heaths with Calluna vulgaris, Carex binervis, Genista anglica, Ulex europaeus and U. gallii.
This species is a perennial scrambling or procumbent shrub, in full flower in late May and June, and pollinated by bees. It sets seed freely, with good recruitment where grazing allows.
In Cornwall, populations number many thousands on the Lizard peninsula (chiefly between Mullion and Caerthillion) and on the north coast between Godrevy Point and Cligga Head. In Pembrokeshire, there are about eleven populations holding 2,000-3,000 plants on St David's Head and Strumble Head. On Cader Idris, it occurs in about seven different locations, with a total of about 90 plants (in 1987). Numbers in particular locations on the mountain vary from about 40 to fewer than ten individuals, but because of the difficult terrain, G. pilosa may be under-recorded there (Morgan 1988a). In Breconshire, a total of 50-60 plants are spread between several colonies (Morgan 1988b). It formerly occurred in several counties in eastern and south-east England, but it has not been seen in its last site, the Ashdown Forest, since 1977, and is presumed everywhere extinct. Current populations appear to be stable.
A threat is posed by intense grazing by sheep at the Breconshire site preventing flowering and fruiting, but some colonies have been enclosed against grazing. Heath fires have destroyed populations in the past, and are a present threat. However, G. pilosa appears not to be significantly threatened at most of its coastal sites. Almost all populations are in SSSIs or on National Trust properties, and are thus afforded a degree of protection against land claim for agriculture, which has caused losses in the past.
G. pilosa occurs in western and central Europe from Spain, eastwards to Albania and Romania, and northwards to southern Sweden. It appears to be in decline in parts of northern and central Europe.
M. J. Wigginton
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.