Description: The mosaic-forming crustose lichen, O. cesareensis can be found by searching the damp gullies and crevices of coastal siliceous rocks. In the field, it is the lilac sheen of the thin, bleached thallus that often draws the attention of the observer. The crooked, scribble-like discs (lirellae) are typically black, with 4-5-septate spores. Exposed coasts and headlands.

Key Identification Features:

• Thin, lilac-grey thallus with scribble-like discs; 4-5-septate under the microscope
• Damp gullies at the foot of siliceous cliff outcrops.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Opegrapha cesareensis at iNaturalist World Species Observations database.