Description: Thallus small narrow, ribbon-like and monostromatic, up to 2 cms long and 1 mm wide, tapering to a distinct uniseriate stipe attached by a disc-shaped holdfast. Cells arranged in groups in longitudinal and transverse rows.

Habitat: Rare. Epilithic, forming a turf at high water mark and above on damp surfaces of cement or brick, sometimes mixed with P.stipitata.

Distribution: A few scattered records in the British Isles. Europe: Spain, France, Germany and Sweden. World wide.

Similar Species: Other species of Prasiola.

Key Identification Features:

• Monostromatic, ribbon-like and small.

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

iNaturalist: Prasiola calophylla at iNaturalist World Species Observations database.

WoRMS: Prasiola calophylla at World Register of Marine Species.