The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
Native; Oceanic, southern-temperate species: France, Spain, Portugal, Channel Islands and a few localities in Britain where it is rare.
It has been found at two sites in Cornwall, but only one is extant. It was discovered near Cape Cornwall (SW33), in West Cornwall, during the nineteenth century and remains at one site near Sladesbridge (SW97), in East Cornwall.
Habitat & Ecology
A perennial plant, it is restricted to two adjacent railway-cuttings, both on steep, rocky
slopes, with a southerly aspect, on thin soils overlying acid rocks. It grows in clearings amongst scrub. The population has fluctuated with management.
Threatened by rapid scrub and tree encroachment at its Cornish locality. Hybridization with Trailing St. John' s-wort H. humifusum is another possible threat.
Recent scrub clearance work has assisted its survival in Cornwall, but Bramble
Rubus fruticosus agg. has taken over cleared areas. This shows the need for ongoing management.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.