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
Encrusting a variety of hard substrata, forming large patches below boulders, and on
the stipes of algae, where it is often abundant. Recorded only from the Isles of Scilly in British waters, where it constitutes a common, and obvious, member of the rocky shore community. It is also found on algae in the sublittoral zone and is very common on fucoid seaweeds on relatively sheltered shores on St. Martin' s and St. Mary' s, IOS (R. Parslow pers comm .). Elsewhere it is widespread throughout the Mediterranean.
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.