An annual of flushed basic turf on sea-cliffs. At its currently known sites, Primula scotica is a constant associate. Lowland.
Though a re-interpretation of herbarium material has resulted in a more restrictive view of this tetraploid taxon than that adopted in Perring & Sell (1968), its taxonomic status remains uncertain. It is apparently derived through hybridisation between E. foulaensis, E. ostenfeldii and E. marshallii and is sometimes hardly distinguishable from the last, with which it regularly grows, when both are dwarfed.
Light (Ellenberg): 8
Moisture (Ellenberg): 4
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 2
Salt Tolerance (Ellenberg): 1
January Mean Temperature (Celsius): 3.5
July Mean Temperature (Celsius): 12.4
Annual Precipitation (mm): 1004
Count of 10km squares in Great Britain: 4
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
RDB Species Accounts
Euphrasia rotundifolia Pugsley (Scrophulariaceae)
Eyebright, Lus nan Leac
Status in Britain: ENDANGERED. ENDEMIC.
As interpreted here, E. rotundifolia is restricted to the northern coast of Scotland between Bettyhill and Melvich in Sutherland, with old records also known from Reay, Caithness. Currently it is certainly known at three sites, all in flushed, basic turf on sea-cliffs, with Primula scotica as a constant associate. Other associated species include Agrostis capillaris, Anthyllis vulneraria, Armeria maritima, Calluna vulgaris, Carex flacca, C. pulicaris, Erica tetralix, Euphrasia foulaensis, Festuca ovina, F. rubra, Parnassia palustris, Plantago maritima and Scilla verna. Populations may be in close proximity to drier cliff edges, occupied by Euphrasia marshallii and Oxytropis halleri, and E. rotundifolia may extend into this microhabitat. It is plausible that other colonies await discovery.
This restricted distribution is at variance with previously published accounts and reflects the uncertain taxonomic status of this species. It was described as a species by Pugsley in 1929, based on a distinctive collection from near Melvich, though he later accepted it as occurring in Shetland and elsewhere.
Subsequently it has been recorded from a number of other sites in northern Scotland. True E. rotundifolia appears to combine features of E. foulaensis and the two densely hairy species, E. marshallii and E. ostenfeldii. Examination of herbarium material and field investigation of reported populations show that records may be based on misidentifications of the two latter species or, more commonly, on recent hybrid swarms between either of them and E. foulaensis. As now interpreted, E. rotundifolia is restricted to the coast at and near its original locality. However, since dwarfed plants of E. marshallii in exposed sites are scarcely distinguishable from similarly dwarfed E. rotundifolia, the latter may yet prove to occur more extensively.
Hybrids are known with E. marshallii and E. foulaensis but do not appear to threaten the pure species. Cultivation of cliff-tops for hay, as at Melvich, has favoured E. arctica, resulting in gene flow into the coastal Euphrasia populations and a potential threat to E. rotundifolia, though the direct hybrid is not yet certainly recorded. E. rotundifolia may have a somewhat later flowering season than related taxa, which would confer some degree of reproductive isolation.
Extension of cultivation at what is believed to be the original site, near Melvich, means that very little suitable habitat now remains and the population is small and highly vulnerable, as is another restricted population near Bettyhill. However, on Strathy Point, plants are scattered over a much larger area, plentiful in some years and isolated from any effects of cultivation.
A. J. Silverside
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.