Lichens : Acarosporales : AcarosporaceaeLichens

Acarospora fuscata (Schrad.) Th.Fr.

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Acarospora fuscata

Description: A not uncommon lichen of nutrient-rich, siliceous rock ledges, brick wall tops, acid rock memorials and the tops of standing stones A. fuscata has the appearance of cracked mud when dry so is easily overlooked. In colour it ranges from pale yellow-brown to warmer reddish-brown tones, the whole thallus appearing shattered like a mirror into angular areoles. The reddish-brown discs sunken into the areoles are more obvious when wet. Look for it on acid rocks where birds are frequent visitors. A dab of bleach will turn the thallus red.

Key Identification Features:

  • Has the appearance of dried mud forming crusts a few centimetres across
  • Mostly on brick walls, low outcrops, churchyard monuments and standing stones; never on limestone

Original text submitted by Vince J. Giavarini

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

iNaturalist: Acarospora fuscata at iNaturalist World Species Observations database.

 Giavarini, Vince J., Simms, Michael J., & Davey, Simon, 2026. Acarospora fuscata. (Schrad.) Th.Fr.. [In] Lichen Ireland.
https://www.habitas.org.uk/lichenireland/species.php?item=18152. Accessed on 2026-11-02.