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
(syn. Pottia asperula Mitt., Pottia wilsonii (Hook.) Bruch & Schimp.). Occurs in S. and W. Europe, from the Mediterranean northwards along Atlantic coasts to the British Isles; also Romania, N. Africa, SW. Asia and Canada (British Columbia). In the British Isles formerly recorded at scattered sites from N. England southwards (including inland localities), but it has declined markedly and is now restricted to the S. and SW. coasts of England, with a few localities in W. Wales.
Recorded on the Isles of Scilly in 1908. Although found in 19 tetrads in Cornwall since 1950, records since 1998 are from only three sites (Pentire Point East, Porthmellin Head, and near Talland Bay) and it has undoubtedly disappeared at several sites where it was known in the 1960s.
Habitat & Ecology
A winter ephemeral that grows on unshaded soil on earthy banks and in the soil of crevices on rocks and Cornish hedges. Capsules are produced in abundance, ripening from January to May.
Reasons for the widespread decline of this species in the British Isles are unknown. There is clear evidence of a recent decline in Cornwall, since many of its old localities have been searched unsuccessfully. One cause of decline is probably the reduction of open coastal habitat due to cessation of grazing on most coastal cliffs. Increased trampling along the coast path may also have caused declines.
Some of the old sites are on protected land, but of the three extant sites only Porthmellin Head is within a SSSI. The species was added to the UK BAP in 2007.
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.