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.
Known in Spain, Italy, Sardinia, the former Yugoslavia, France, Denmark, Sweden, N. Russia and Madeira. In the British Isles it is known only in Cornwall.
Known only in two small areas on the Lizard (in SW61 up to 1968; discovered W. of Rosuic in SW72 in 2004). Formerly also on Lizard Downs, where it was recorded from 1926-1938 (Paton, 1969).
00 Habitat & Ecology
Grows on tracks and in hollows liable to periodic shallow flooding, on heathland overlying serpentine bedrock. It is a dioicous species in which perianths have been recorded, but male plants are unknown. Foliar gemmae are frequently produced.
There is little recent information on the status of the species in Cornwall. A tiny population was discovered on the E. Lizard in 2004 but it might now be extinct on the W. Lizard (SW61), although sites there still have good heathland habitats. Another rare plant of old heathland trackways on the Lizard, Pigmy Rush Juncus pygmaeus , has declined markedly since the 1980s, implying an urgent need for a detailed survey of the present status of C. dentata .
All Cornish sites are within SSSI. Treated as Critically Endangered in Red-list (Church et al ., 2001). This species is listed on the UK BAP Priority Species list (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.