Description: Thalli erect and flattened, thin and membranous with terete stipe. Blades delicate to over 35 cms long and 6 cms wide. Midrib distinct, veins opposite and branch as secondary veins.

Habitat: Epilithic in the sublittoral to at least 18 m.

Distribution: British Isles: south and western coasts. Europe: Mediterranean, Spain and France.

Similar Species: Desmarestia ligulata is much branched; Laminaria saccharina is thick and leatherly.

Key Identification Features:

• Thin membraneous unbranched easily torn frond.

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

iNaturalist: Desmarestia dresnayi at iNaturalist World Species Observations database.

WoRMS: Desmarestia dresnayi at World Register of Marine Species. Accepted name: Desmarestia dudresnayi J.V.Lamouroux ex Léman, 1819. AphiaID: 295864.

Classification: Biota; Chromista; Harosa; Heterokonta; Ochrophyta; Phaeophyceae; Fucophycidae; Desmarestiales; Desmarestiaceae; Desmarestia