Cornish Biodiversity Network  -  Supporting Wildlife Recording

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Cornish Red Data (2009)

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.

Cystopteris diaphana - Diaphanous Bladder-fern

Range & Status

Native; found in Corsica, France, Italy, Portugal, Sicily, Spain and the Azores (Murphy,

Page & Parslow, in prep.). Since its discovery in Cornwall it has been found near Tavistock in Devon and in Ireland.

Regional Distribution

Found along a short stretch of the lower reaches of the River Camel in North Cornwall, just above the tidal limit (SX06 & SX07). Originally found and recorded as Cystopteris fragilis here in 2000, but re-determination in 2003 confirmed the plants as Cystopteris diaphana ; new to the British Isles.

Habitat & Ecology

On bare muddy places and between tree roots on vertical riverbanks that are subjected to winter flooding, and on nearby damp wooded banks.




The River Camel is a SAC and most of the site lies on Forestry Commission land.

Click here to see Aphotoflora images by David Fenwick


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.