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.
This stonewort is restricted to the Atlantic coastal regions of Europe and North Africa. In Europe it occurs in Portugal, Spain and France and reaches its northern limit in west Cornwall. Here it has been recorded at one time from scattered sites on the Isles of Scilly, West Penwith, the Lizard Peninsula and reaching east towards the Falmouth area. It seems always to have been rare outside the Lizard and is now restricted to that peninsula. Here there are some very good populations and at least 37 populations are known since 1989. Stewart (2003) has listed the Cornish records. Strawberry Stonewort is a species found in shallow, standing water which is low in nutrients. Here it can grow on peaty, clayey or gravelly substrates in the three main situations: small quarry pits, rutted trackways and large, but shallow, pools all normally overlying ultramafic serpentine rock. Despite the apparent size and stability of the Lizard populations at present there are several threats that have, or may become, problems. Nutrient enrichment, succession, management of trackways and the introduction of alien aquatic plants such as Curly Water Thyme Lagarosiphon major , which out-competes the stonewort in deeper water, are potential threats. Most of the populations on the Lizard Peninsula lie within SSSIs or National Nature Reserves.
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.