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
An introduced species found in the subtidal fringe where it grows epilithically on the
bedrock (granite) and boulders in sites very exposed to wave action and semi-exposed to tidal streams, in up to 5m depth of water. Previously only known from southern British Columbia to California and Japan in the Pacific Ocean. The records from the Isles of Scilly are the first and only records for the north-east Atlantic. Originally found in 1967 (but not then identified), it has since been found in relatively high abundance in numerous sites which suggests that, although originally an immigrant species, it is now a permanent feature of the marine flora of the archipelago.
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.