Description: Hard crusts up to 5 cms across, adherent except at the margins. When dry, clear striations are visible and the margins curle up.

Habitat: Rarely recorded. Epilithic or epiphytic on coralline algae or kelp holdfasts in the upper sublittoral and to a depth of 12 m.

Distribution: Widely distributed around the British Isles. Europe: Mediterranean, Portugal and Spain. Further afield: Canary Islands.

Similar Species: Other species of Peyssonnelia.

Key Identification Features:

• Distinguished by radial striations seen best when dry.

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

iNaturalist: Peyssonnelia harveyana at iNaturalist World Species Observations database.

GBIF data for Agissea harveyana

WoRMS: Peyssonnelia harveyana at World Register of Marine Species. Accepted name: Agissea harveyana (P.Crouan & H.Crouan ex J.Agardh) Pestana, Lyra, Cassano & J.M.C. Nunes, 2021. AphiaID: 1639615.

Classification: Biota; Plantae; Biliphyta; Rhodophyta; Eurhodophytina; Florideophyceae; Rhodymeniophycidae; Peyssonneliales; Peyssonneliaceae; Peyssonnelia