Description: The gelatinous frond grows from discoid base with a short stipe expanding to 30 cms long and up to 10 cms broad. The flattened blade branches dichotomously.

Habitat: Very rare. Deep rock pools in the upper sublittoral.

Distribution: British Isles: south west Ireland, England (Cornwall), Wales and the Channel Islands. Europe: Spain and France. Further afield: Canary Islands.

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

iNaturalist: Itonoa marginifera at iNaturalist World Species Observations database.

WoRMS: Itonoa marginifera at World Register of Marine Species. Accepted name: Itonoa marginifera (J.Agardh) Masuda & Guiry, 1995. AphiaID: 145638.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Nemastomatales; Nemastomataceae; Itonoa