Description: Solid and globose when young, hollow and irregular later. Growing to about 5 cms in diameter. Fleshy and mucilaginous, separating into irregular lumps when squeezed.

Habitat: Very common and widespread. Epiphytic, occasionally epilithic, in rock pools of the littoral.

Distribution: Widespread around the British Isles from the Shetlands to the Channel Islands. Europe: Mediterranean and the Black Sea, Azores, Portugal, Spain, France, Netherlands, Germany, Baltic Sea, Sweden, Norway, Faroes and Iceland. Atlantic coast of North America: Canada, Maine, New Hampshire, Massachusetts, Connecticut, Long Island, Delaware, Virginia and North Carolina. Further afield: Tunisia in the Mediterranean. Atlantic: the Canary Islands, Morocco, Mauritania, Namibia, South Africa, Tristan da Cunha. Pacific America: Bearing Sea, Commander Islands, Alaska, British Columbia, Oregon, California. West Pacific: Phillipines and Japan. South Australia, Tasmania and New Zealand.

Similar Species: Colpomenia peregrina. However Leathesia is thick walled and mucilaginous Colpomenia is a thin walled.

Key Identification Features:

• A gelatinous, irregularly shaped bulbous mass up to 5 cms in diameter.

Distribution Map from NBN: Leathesia difformis at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Leathesia difformis at iNaturalist World Species Observations database.

WoRMS: Leathesia difformis at World Register of Marine Species. Accepted name: Leathesia marina (Lyngbye) Decaisne, 1842. AphiaID: 494940.

Classification: Biota; Chromista; Harosa; Heterokonta; Ochrophyta; Phaeophyceae; Fucophycidae; Ectocarpales; Chordariaceae; Leathesia